diff --git a/packages/@aws-cdk/aws-kms/lib/key.ts b/packages/@aws-cdk/aws-kms/lib/key.ts
index 20c8f4506a77b..47b6a64edeff8 100644
--- a/packages/@aws-cdk/aws-kms/lib/key.ts
+++ b/packages/@aws-cdk/aws-kms/lib/key.ts
@@ -37,7 +37,7 @@ export interface EncryptionKeyImportProps {
   keyArn: string;
 }
 
-export abstract class EncryptionKeyBase extends Construct {
+export abstract class EncryptionKeyBase extends Construct implements IEncryptionKey {
   /**
    * The ARN of the key.
    */