diff --git a/types/jws/index.d.ts b/types/jws/index.d.ts
index f384fadefc..fdbf1851c4 100644
--- a/types/jws/index.d.ts
+++ b/types/jws/index.d.ts
@@ -149,4 +149,5 @@ export type Algorithm = 'HS256' | 'HS384' | 'HS512' | 'RS256' |
 
 export interface Header {
     alg: Algorithm;
+    [name: string]: string;
 }
diff --git a/types/jws/jws-tests.ts b/types/jws/jws-tests.ts
index d5271b24ca..c6e62378f8 100644
--- a/types/jws/jws-tests.ts
+++ b/types/jws/jws-tests.ts
@@ -20,6 +20,13 @@ const signature = jws.sign({
   secret: 'has a van',
 });
 
+// jws.sign with extra header values
+const signatureWithHeaderParams = jws.sign({
+  header: { alg: 'HS256', foo: 'bar' },
+  payload: 'h. jon benjamin',
+  secret: 'has a van',
+});
+
 // jws.decode
 const message = jws.decode('djfakdid');