diff --git a/src/wp-admin/js/widgets/media-widgets.js b/src/wp-admin/js/widgets/media-widgets.js
index 54862f582b..d1f015f605 100644
--- a/src/wp-admin/js/widgets/media-widgets.js
+++ b/src/wp-admin/js/widgets/media-widgets.js
@@ -255,7 +255,7 @@ wp.mediaWidgets = ( function( $ ) {
 				}
 			});
 			if ( specificMimes.length > 0 ) {
-				mime = specificMimes.join( ',' );
+				mime = specificMimes;
 			}
 
 			this.states.add([