diff --git a/async-nats/src/auth.rs b/async-nats/src/auth.rs
index e04e72455..968c5c6da 100644
--- a/async-nats/src/auth.rs
+++ b/async-nats/src/auth.rs
@@ -5,7 +5,7 @@ pub struct Auth {
     pub jwt: Option<String>,
     pub nkey: Option<String>,
     pub(crate) signature_callback: Option<CallbackArg1<String, Result<String, AuthError>>>,
-    pub signature: Option<String>,
+    pub signature: Option<Vec<u8>>,
     pub username: Option<String>,
     pub password: Option<String>,
     pub token: Option<String>,
diff --git a/async-nats/tests/client_tests.rs b/async-nats/tests/client_tests.rs
index 9efd2055f..a9b1dcba1 100644
--- a/async-nats/tests/client_tests.rs
+++ b/async-nats/tests/client_tests.rs
@@ -887,6 +887,28 @@ mod client {
         .unwrap();
     }
 
+    #[tokio::test]
+    async fn custom_auth_callback_jwt() {
+        let server = nats_server::run_server("tests/configs/jwt.conf");
+
+        ConnectOptions::with_auth_callback(move |nonce| async move {
+            let mut auth = async_nats::Auth::new();
+            auth.jwt = Some("eyJ0eXAiOiJKV1QiLCJhbGciOiJlZDI1NTE5LW5rZXkifQ.".to_owned() +
+                "eyJqdGkiOiJMN1dBT1hJU0tPSUZNM1QyNEhMQ09ENzJRT1czQkNVWEdETjRKVU1SSUtHTlQ3RzdZVFRRIiwiaWF0IjoxNjUxNzkwOTgyLCJpc3MiOiJBRFRRUzdaQ0ZWSk5XNTcyNkdPWVhXNVRTQ1pGTklRU0hLMlpHWVVCQ0Q1RDc3T1ROTE9PS1pPWiIsIm5hbWUiOiJUZXN0V" +
+                "XNlciIsInN1YiI6IlVBRkhHNkZVRDJVVTRTREZWQUZVTDVMREZPMlhNNFdZTTc2VU5YVFBKWUpLN0VFTVlSQkhUMlZFIiwibmF0cyI6eyJwdWIiOnt9LCJzdWIiOnt9LCJzdWJzIjotMSwiZGF0YSI6LTEsInBheWxvYWQiOi0xLCJ0eXBlIjoidXNlciIsInZlcnNpb24iOjJ9fQ." +
+                "bp2-Jsy33l4ayF7Ku1MNdJby4WiMKUrG-rSVYGBusAtV3xP4EdCa-zhSNUaBVIL3uYPPCQYCEoM1pCUdOnoJBg");
+
+            let key_pair = nkeys::KeyPair::from_seed("SUACH75SWCM5D2JMJM6EKLR2WDARVGZT4QC6LX3AGHSWOMVAKERABBBRWM").unwrap();
+            let sign = key_pair.sign(&nonce).map_err(async_nats::AuthError::new)?;
+            auth.signature = Some(sign);
+
+            Ok(auth)
+        })
+        .connect(server.client_url())
+        .await
+        .unwrap();
+    }
+
     #[tokio::test]
     async fn max_reconnects() {
         let (tx, mut rx) = tokio::sync::mpsc::unbounded_channel();