diff --git a/src/Framework/MockObject/Runtime/Api/MockObjectApi.php b/src/Framework/MockObject/Runtime/Api/MockObjectApi.php
index 92121546698..e348c0f2c20 100644
--- a/src/Framework/MockObject/Runtime/Api/MockObjectApi.php
+++ b/src/Framework/MockObject/Runtime/Api/MockObjectApi.php
@@ -22,7 +22,6 @@
 trait MockObjectApi
 {
     private static array $__phpunit_deprecation_emitted_for_test = [];
-    private object $__phpunit_originalObject;
 
     /** @noinspection MagicMethodsValidityInspection */
     public function __phpunit_hasMatchers(): bool
@@ -30,12 +29,6 @@ public function __phpunit_hasMatchers(): bool
         return $this->__phpunit_getInvocationHandler()->hasMatchers();
     }
 
-    /** @noinspection MagicMethodsValidityInspection */
-    public function __phpunit_setOriginalObject(object $originalObject): void
-    {
-        $this->__phpunit_originalObject = $originalObject;
-    }
-
     /** @noinspection MagicMethodsValidityInspection */
     public function __phpunit_verify(bool $unsetInvocationMocker = true): void
     {
diff --git a/src/Framework/MockObject/Runtime/Interface/MockObjectInternal.php b/src/Framework/MockObject/Runtime/Interface/MockObjectInternal.php
index bb84ffaccb6..0952566774a 100644
--- a/src/Framework/MockObject/Runtime/Interface/MockObjectInternal.php
+++ b/src/Framework/MockObject/Runtime/Interface/MockObjectInternal.php
@@ -16,7 +16,5 @@ interface MockObjectInternal extends MockObject, StubInternal
 {
     public function __phpunit_hasMatchers(): bool;
 
-    public function __phpunit_setOriginalObject(object $originalObject): void;
-
     public function __phpunit_verify(bool $unsetInvocationMocker = true): void;
 }