diff --git a/wp-includes/category-template.php b/wp-includes/category-template.php
index 8cf66c53bc..e45734abbb 100644
--- a/wp-includes/category-template.php
+++ b/wp-includes/category-template.php
@@ -1062,9 +1062,6 @@ function get_the_terms( $post, $taxonomy ) {
 	if ( ! $post = get_post( $post ) )
 		return false;
 
-	if ( ! is_object_in_taxonomy( $post->post_type, $taxonomy ) )
-		return false;
-
 	$terms = get_object_term_cache( $post->ID, $taxonomy );
 	if ( false === $terms ) {
 		$terms = wp_get_object_terms( $post->ID, $taxonomy );
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 1cc76b9af9..3eaa5620d4 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -615,16 +615,20 @@ final class WP_Post {
 		}
 
 		if ( 'post_category' == $key ) {
-			$terms = get_the_terms( $this, 'category' );
-			if ( ! $terms )
+			if ( is_object_in_taxonomy( $this->post_type, 'category' ) )
+				$terms = get_the_terms( $this, 'category' );
+
+			if ( empty( $terms ) )
 				return array();
 
 			return wp_list_pluck( $terms, 'term_id' );
 		}
 
 		if ( 'tags_input' == $key ) {
-			$terms = get_the_terms( $this, 'post_tag' );
-			if ( ! $terms )
+			if ( is_object_in_taxonomy( $this->post_type, 'post_tag' ) )
+				$terms = get_the_terms( $this, 'post_tag' );
+
+			if ( empty( $terms ) )
 				return array();
 
 			return wp_list_pluck( $terms, 'name' );