diff --git a/src/js/plyr.d.ts b/src/js/plyr.d.ts
index cdd5cd4c..aca14d9a 100644
--- a/src/js/plyr.d.ts
+++ b/src/js/plyr.d.ts
@@ -552,7 +552,7 @@ declare namespace Plyr {
 
   interface PreviewThumbnailsOptions {
     enabled?: boolean;
-    src?: string;
+    src?: string | string[];
   }
 
   interface SourceInfo {