diff --git a/types/aws-lambda/index.d.ts b/types/aws-lambda/index.d.ts
index dd3fd3bd4e..4c10da216f 100644
--- a/types/aws-lambda/index.d.ts
+++ b/types/aws-lambda/index.d.ts
@@ -404,7 +404,7 @@ export interface CognitoIdentity {
 
 export interface ClientContext {
     client: ClientContextClient;
-    Custom?: any;
+    custom?: any;
     env: ClientContextEnv;
 }