diff --git a/ext/soap/php_soap.h b/ext/soap/php_soap.h
index a78734aa7f17..d98235b68b73 100644
--- a/ext/soap/php_soap.h
+++ b/ext/soap/php_soap.h
@@ -223,35 +223,34 @@ static zend_always_inline zval *php_soap_deref(zval *zv) {
 #define Z_CLIENT_TRACE_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 4))
 #define Z_CLIENT_COMPRESSION_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 5))
 #define Z_CLIENT_SDL_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 6))
-#define Z_CLIENT_TYPEMAP_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 7))
-#define Z_CLIENT_HTTPSOCKET_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 8))
-#define Z_CLIENT_HTTPURL_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 9))
-#define Z_CLIENT_LOGIN_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 10))
-#define Z_CLIENT_PASSWORD_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 11))
-#define Z_CLIENT_USE_DIGEST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 12))
-#define Z_CLIENT_DIGEST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 13))
-#define Z_CLIENT_PROXY_HOST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 14))
-#define Z_CLIENT_PROXY_PORT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 15))
-#define Z_CLIENT_PROXY_LOGIN_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 16))
-#define Z_CLIENT_PROXY_PASSWORD_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 17))
-#define Z_CLIENT_EXCEPTIONS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 18))
-#define Z_CLIENT_ENCODING_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 19))
-#define Z_CLIENT_CLASSMAP_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 20))
-#define Z_CLIENT_FEATURES_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 21))
-#define Z_CLIENT_CONNECTION_TIMEOUT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 22))
-#define Z_CLIENT_STREAM_CONTEXT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 23))
-#define Z_CLIENT_USER_AGENT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 24))
-#define Z_CLIENT_KEEP_ALIVE_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 25))
-#define Z_CLIENT_SSL_METHOD_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 26))
-#define Z_CLIENT_SOAP_VERSION_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 27))
-#define Z_CLIENT_USE_PROXY_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 28))
-#define Z_CLIENT_COOKIES_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 29))
-#define Z_CLIENT_DEFAULT_HEADERS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 30))
-#define Z_CLIENT_SOAP_FAULT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 31))
-#define Z_CLIENT_LAST_REQUEST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 32))
-#define Z_CLIENT_LAST_RESPONSE_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 33))
-#define Z_CLIENT_LAST_REQUEST_HEADERS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 34))
-#define Z_CLIENT_LAST_RESPONSE_HEADERS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 35))
+#define Z_CLIENT_HTTPSOCKET_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 7))
+#define Z_CLIENT_HTTPURL_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 8))
+#define Z_CLIENT_LOGIN_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 9))
+#define Z_CLIENT_PASSWORD_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 10))
+#define Z_CLIENT_USE_DIGEST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 11))
+#define Z_CLIENT_DIGEST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 12))
+#define Z_CLIENT_PROXY_HOST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 13))
+#define Z_CLIENT_PROXY_PORT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 14))
+#define Z_CLIENT_PROXY_LOGIN_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 15))
+#define Z_CLIENT_PROXY_PASSWORD_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 16))
+#define Z_CLIENT_EXCEPTIONS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 17))
+#define Z_CLIENT_ENCODING_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 18))
+#define Z_CLIENT_CLASSMAP_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 19))
+#define Z_CLIENT_FEATURES_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 20))
+#define Z_CLIENT_CONNECTION_TIMEOUT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 21))
+#define Z_CLIENT_STREAM_CONTEXT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 22))
+#define Z_CLIENT_USER_AGENT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 23))
+#define Z_CLIENT_KEEP_ALIVE_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 24))
+#define Z_CLIENT_SSL_METHOD_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 25))
+#define Z_CLIENT_SOAP_VERSION_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 26))
+#define Z_CLIENT_USE_PROXY_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 27))
+#define Z_CLIENT_COOKIES_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 28))
+#define Z_CLIENT_DEFAULT_HEADERS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 29))
+#define Z_CLIENT_SOAP_FAULT_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 30))
+#define Z_CLIENT_LAST_REQUEST_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 31))
+#define Z_CLIENT_LAST_RESPONSE_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 32))
+#define Z_CLIENT_LAST_REQUEST_HEADERS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 33))
+#define Z_CLIENT_LAST_RESPONSE_HEADERS_P(zv) php_soap_deref(OBJ_PROP_NUM(Z_OBJ_P(zv), 34))
 
 typedef struct soap_url_object {
 	php_url *url;
diff --git a/ext/soap/soap.c b/ext/soap/soap.c
index ac14dee76cf0..fd3a0b3c0440 100644
--- a/ext/soap/soap.c
+++ b/ext/soap/soap.c
@@ -185,6 +185,7 @@ zend_class_entry* soap_var_class_entry;
 zend_class_entry *soap_url_class_entry;
 zend_class_entry *soap_sdl_class_entry;
 
+static zend_object_handlers soap_client_object_handlers;
 static zend_object_handlers soap_server_object_handlers;
 static zend_object_handlers soap_url_object_handlers;
 static zend_object_handlers soap_sdl_object_handlers;
@@ -194,10 +195,36 @@ typedef struct {
 	zend_object std;
 } soap_server_object;
 
+typedef struct {
+	HashTable *typemap;
+	zend_object std;
+} soap_client_object;
+
+static inline soap_client_object *soap_client_object_fetch(zend_object *obj) {
+	return (soap_client_object *) ((char *) obj - XtOffsetOf(soap_client_object, std));
+}
+
 static inline soap_server_object *soap_server_object_fetch(zend_object *obj) {
 	return (soap_server_object *) ((char *) obj - XtOffsetOf(soap_server_object, std));
 }
 
+static zend_object *soap_client_object_create(zend_class_entry *ce)
+{
+	soap_client_object *obj = zend_object_alloc(sizeof(soap_client_object), ce);
+	zend_object_std_init(&obj->std, ce);
+	object_properties_init(&obj->std, ce);
+	return &obj->std;
+}
+
+static void soap_client_object_free(zend_object *obj) {
+	soap_client_object *client_obj = soap_client_object_fetch(obj);
+	if (client_obj->typemap) {
+		zend_hash_destroy(client_obj->typemap);
+		FREE_HASHTABLE(client_obj->typemap);
+	}
+	zend_object_std_dtor(obj);
+}
+
 static zend_object *soap_server_object_create(zend_class_entry *ce)
 {
 	soap_server_object *obj = zend_object_alloc(sizeof(soap_server_object), ce);
@@ -496,6 +523,13 @@ PHP_MINIT_FUNCTION(soap)
 
 	/* Register SoapClient class */
 	soap_class_entry = register_class_SoapClient();
+	soap_class_entry->create_object = soap_client_object_create;
+	soap_class_entry->default_object_handlers = &soap_client_object_handlers;
+
+	memcpy(&soap_client_object_handlers, &std_object_handlers, sizeof(zend_object_handlers));
+	soap_client_object_handlers.offset = XtOffsetOf(soap_client_object, std);
+	soap_client_object_handlers.free_obj = soap_client_object_free;
+	soap_client_object_handlers.clone_obj = NULL;
 
 	/* Register SoapVar class */
 	soap_var_class_entry = register_class_SoapVar();
@@ -1978,6 +2012,7 @@ PHP_FUNCTION(is_soap_fault)
 /* SoapClient functions */
 
 /* {{{ SoapClient constructor */
+/* FIXME: double construct call will break this class */
 PHP_METHOD(SoapClient, __construct)
 {
 
@@ -2201,10 +2236,7 @@ PHP_METHOD(SoapClient, __construct)
 	}
 
 	if (typemap_ht) {
-		HashTable *typemap = soap_create_typemap(sdl, typemap_ht);
-		if (typemap) {
-			ZVAL_ARR(Z_CLIENT_TYPEMAP_P(this_ptr), typemap);
-		}
+		soap_client_object_fetch(Z_OBJ_P(this_ptr))->typemap = soap_create_typemap(sdl, typemap_ht);
 	}
 	SOAP_CLIENT_END_CODE();
 }
@@ -2333,10 +2365,7 @@ static void do_soap_call(zend_execute_data *execute_data,
 		sdl = Z_SOAP_SDL_P(tmp)->sdl;
 	}
 
-	tmp = Z_CLIENT_TYPEMAP_P(this_ptr);
-	if (Z_TYPE_P(tmp) == IS_ARRAY) {
-		typemap = Z_ARR_P(tmp);
-	}
+	typemap = soap_client_object_fetch(Z_OBJ_P(this_ptr))->typemap;
 
 	clear_soap_fault(this_ptr);
 
diff --git a/ext/soap/soap.stub.php b/ext/soap/soap.stub.php
index 82f884e24b30..b70a050bfe3a 100644
--- a/ext/soap/soap.stub.php
+++ b/ext/soap/soap.stub.php
@@ -540,7 +540,6 @@ class SoapClient
         private bool $trace = false;
         private ?int $compression = null;
         private ?Soap\Sdl $sdl = null;
-        private ?array $typemap = null;
         /** @var resource|null */
         private $httpsocket = null;
         private ?Soap\Url $httpurl = null;
diff --git a/ext/soap/soap_arginfo.h b/ext/soap/soap_arginfo.h
index ca0d2d9644e8..6311aa2b4203 100644
--- a/ext/soap/soap_arginfo.h
+++ b/ext/soap/soap_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 7712aba90b16090fbe7c124c1e3f26b2cc3e2ab2 */
+ * Stub hash: b3b0e1ba5c8516493a0e323231d203659131338f */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_use_soap_error_handler, 0, 0, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, enable, _IS_BOOL, 0, "true")
@@ -562,12 +562,6 @@ static zend_class_entry *register_class_SoapClient(void)
 	zend_declare_typed_property(class_entry, property_sdl_name, &property_sdl_default_value, ZEND_ACC_PRIVATE, NULL, (zend_type) ZEND_TYPE_INIT_CLASS(property_sdl_class_Soap_Sdl, 0, MAY_BE_NULL));
 	zend_string_release(property_sdl_name);
 
-	zval property_typemap_default_value;
-	ZVAL_NULL(&property_typemap_default_value);
-	zend_string *property_typemap_name = zend_string_init("typemap", sizeof("typemap") - 1, 1);
-	zend_declare_typed_property(class_entry, property_typemap_name, &property_typemap_default_value, ZEND_ACC_PRIVATE, NULL, (zend_type) ZEND_TYPE_INIT_MASK(MAY_BE_ARRAY|MAY_BE_NULL));
-	zend_string_release(property_typemap_name);
-
 	zval property_httpsocket_default_value;
 	ZVAL_NULL(&property_httpsocket_default_value);
 	zend_string *property_httpsocket_name = zend_string_init("httpsocket", sizeof("httpsocket") - 1, 1);
diff --git a/ext/soap/tests/bugs/gh21421.phpt b/ext/soap/tests/bugs/gh21421.phpt
new file mode 100644
index 000000000000..1b8bb3be716f
--- /dev/null
+++ b/ext/soap/tests/bugs/gh21421.phpt
@@ -0,0 +1,90 @@
+--TEST--
+GH-21421 (SoapClient typemap property breaks engine assumptions)
+--EXTENSIONS--
+soap
+--FILE--
+<?php
+$options = array(
+'uri'      => 'http://schemas.nothing.com',
+'location' => 'test://',
+'typemap'  => array(array("type_ns"   => "http://schemas.nothing.com",
+"type_name" => "book",
+"from_xml"  => "book_from_xml"))
+);
+$client = new SoapClient(NULL, $options);
+var_dump($client);
+?>
+--EXPECTF--
+object(SoapClient)#%d (35) {
+  ["uri":"SoapClient":private]=>
+  string(26) "http://schemas.nothing.com"
+  ["style":"SoapClient":private]=>
+  NULL
+  ["use":"SoapClient":private]=>
+  NULL
+  ["location":"SoapClient":private]=>
+  string(7) "test://"
+  ["trace":"SoapClient":private]=>
+  bool(false)
+  ["compression":"SoapClient":private]=>
+  NULL
+  ["sdl":"SoapClient":private]=>
+  NULL
+  ["httpsocket":"SoapClient":private]=>
+  NULL
+  ["httpurl":"SoapClient":private]=>
+  NULL
+  ["_login":"SoapClient":private]=>
+  NULL
+  ["_password":"SoapClient":private]=>
+  NULL
+  ["_use_digest":"SoapClient":private]=>
+  bool(false)
+  ["_digest":"SoapClient":private]=>
+  NULL
+  ["_proxy_host":"SoapClient":private]=>
+  NULL
+  ["_proxy_port":"SoapClient":private]=>
+  NULL
+  ["_proxy_login":"SoapClient":private]=>
+  NULL
+  ["_proxy_password":"SoapClient":private]=>
+  NULL
+  ["_exceptions":"SoapClient":private]=>
+  bool(true)
+  ["_encoding":"SoapClient":private]=>
+  NULL
+  ["_classmap":"SoapClient":private]=>
+  NULL
+  ["_features":"SoapClient":private]=>
+  NULL
+  ["_connection_timeout":"SoapClient":private]=>
+  int(0)
+  ["_stream_context":"SoapClient":private]=>
+  resource(%d) of type (stream-context)
+  ["_user_agent":"SoapClient":private]=>
+  NULL
+  ["_keep_alive":"SoapClient":private]=>
+  bool(true)
+  ["_ssl_method":"SoapClient":private]=>
+  NULL
+  ["_soap_version":"SoapClient":private]=>
+  int(1)
+  ["_use_proxy":"SoapClient":private]=>
+  NULL
+  ["_cookies":"SoapClient":private]=>
+  array(0) {
+  }
+  ["__default_headers":"SoapClient":private]=>
+  NULL
+  ["__soap_fault":"SoapClient":private]=>
+  NULL
+  ["__last_request":"SoapClient":private]=>
+  NULL
+  ["__last_response":"SoapClient":private]=>
+  NULL
+  ["__last_request_headers":"SoapClient":private]=>
+  NULL
+  ["__last_response_headers":"SoapClient":private]=>
+  NULL
+}