diff --git a/plugins/system/languagecode/languagecode.php b/plugins/system/languagecode/languagecode.php
index 9826fc01cd519..b10bb5d6d19a3 100644
--- a/plugins/system/languagecode/languagecode.php
+++ b/plugins/system/languagecode/languagecode.php
@@ -113,16 +113,8 @@ public function onAfterRender()
 	 *
 	 * @since	2.5
 	 */
-	public function onContentPrepareForm($form, $data)
+	public function onContentPrepareForm(JForm $form, $data)
 	{
-		// Check we have a form.
-		if (!($form instanceof JForm))
-		{
-			$this->_subject->setError('JERROR_NOT_A_FORM');
-
-			return false;
-		}
-
 		// Check we are manipulating the languagecode plugin.
 		if ($form->getName() !== 'com_plugins.plugin' || !$form->getField('languagecodeplugin', 'params'))
 		{
diff --git a/plugins/user/profile/profile.php b/plugins/user/profile/profile.php
index e9b2253945caa..0bc82ca8657a2 100644
--- a/plugins/user/profile/profile.php
+++ b/plugins/user/profile/profile.php
@@ -224,15 +224,8 @@ public static function tos($value)
 	 *
 	 * @since   1.6
 	 */
-	public function onContentPrepareForm($form, $data)
+	public function onContentPrepareForm(JForm $form, $data)
 	{
-		if (!($form instanceof JForm))
-		{
-			$this->_subject->setError('JERROR_NOT_A_FORM');
-
-			return false;
-		}
-
 		// Check we are manipulating a valid form.
 		$name = $form->getName();