diff --git a/src/wp-includes/link-template.php b/src/wp-includes/link-template.php
index 4264d784ef..9ba51f4e1d 100644
--- a/src/wp-includes/link-template.php
+++ b/src/wp-includes/link-template.php
@@ -2417,7 +2417,8 @@ function wp_get_shortlink($id = 0, $context = 'post', $allow_slugs = true) {
 		$post = get_post( $post_id );
 	} elseif ( 'post' == $context ) {
 		$post = get_post( $id );
-		$post_id = $post->ID;
+		if ( ! empty( $post->ID ) )
+			$post_id = $post->ID;
 	}
 
 	$shortlink = '';
diff --git a/tests/phpunit/tests/link.php b/tests/phpunit/tests/link.php
index 13ab21f176..42ebc3f4b6 100644
--- a/tests/phpunit/tests/link.php
+++ b/tests/phpunit/tests/link.php
@@ -35,6 +35,8 @@ class Tests_Link extends WP_UnitTestCase {
 		// Basic case
 		$this->assertEquals( get_permalink( $post_id ), wp_get_shortlink( $post_id, 'post' ) );
 
+		unset( $GLOBALS['post'] );
+
 		// Global post is not set
 		$this->assertEquals( '', wp_get_shortlink( 0, 'post' ) );
 		$this->assertEquals( '', wp_get_shortlink( 0 ) );