diff --git a/ext/soap/soap.c b/ext/soap/soap.c
index dec44c68575..0ce74898cf5 100644
--- a/ext/soap/soap.c
+++ b/ext/soap/soap.c
@@ -3550,7 +3550,7 @@ static xmlDocPtr serialize_response_call(sdlFunctionPtr function, char *function
 
 			head = xmlNewChild(envelope, ns, "Header", NULL);
 			if (Z_TYPE_P(hdr_ret) == IS_OBJECT &&
-			    instanceof_function(Z_OBJCE_P(hdr_ret), soap_header_class_entry)) {
+			    instanceof_function(Z_OBJCE_P(hdr_ret), soap_header_class_entry TSRMLS_CC)) {
 				HashTable* ht = Z_OBJPROP_P(hdr_ret);
 				zval **tmp;
 				sdlSoapBindingFunctionHeaderPtr *hdr;