diff --git a/types/vast-client/index.d.ts b/types/vast-client/index.d.ts
index 9886554e88..639b940a04 100644
--- a/types/vast-client/index.d.ts
+++ b/types/vast-client/index.d.ts
@@ -231,9 +231,14 @@ export interface VastError {
     ERRORCODE: string;
 }
 
+export interface VastCreative {
+    0: VastCreativeLinear,
+    1: VastCreativeCompanion
+}
+
 export interface VastAd {
     advertiser: any;
-    creatives: VastCreativeLinear | VastCreativeCompanion[];
+    creatives: VastCreative[];
     description: string;
     errorURLTemplates: string[];
     extensions: VastAdExtension[];