diff --git a/aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/CognitoUserPoolPreTokenGenerationEventV2.java b/aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/CognitoUserPoolPreTokenGenerationEventV2.java
index c7250570..9faeb970 100644
--- a/aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/CognitoUserPoolPreTokenGenerationEventV2.java
+++ b/aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/CognitoUserPoolPreTokenGenerationEventV2.java
@@ -127,8 +127,8 @@ public static class AccessTokenGeneration {
     @Builder(setterPrefix = "with")
     @NoArgsConstructor
     public static class GroupOverrideDetails {
-        private Map<String, String> groupsToOverride;
-        private Map<String, String> iamRolesToOverride;
+        private String[] groupsToOverride;
+        private String[] iamRolesToOverride;
         private String preferredRole;
     }
 }
\ No newline at end of file