diff --git a/test/types/client.test-d.ts b/test/types/client.test-d.ts
index ed50d85194d..a1e8b62af79 100644
--- a/test/types/client.test-d.ts
+++ b/test/types/client.test-d.ts
@@ -319,4 +319,15 @@ expectAssignable<Client>(
   expectType<number>(client.stats.pending)
   expectType<number>(client.stats.running)
   expectType<number>(client.stats.size)
+
+  // opaque
+  expectType<Promise<Dispatcher.ConnectData<number>>>(
+    client.connect({ opaque: 123, path: '' })
+  )
+  expectType<Promise<Dispatcher.ConnectData<null>>>(
+    client.connect({ path: '' })
+  )
+  expectType<Promise<Dispatcher.ConnectData<{ foo: string }>>>(
+    client.connect({ opaque: { foo: 'bar' }, path: '' })
+  )
 }
diff --git a/types/client.d.ts b/types/client.d.ts
index a6e20221f68..7521368c26b 100644
--- a/types/client.d.ts
+++ b/types/client.d.ts
@@ -3,7 +3,7 @@ import Dispatcher from './dispatcher'
 import buildConnector from './connector'
 import TClientStats from './client-stats'
 
-type ClientConnectOptions = Omit<Dispatcher.ConnectOptions, 'origin'>
+type ClientConnectOptions<TOpaque = null> = Omit<Dispatcher.ConnectOptions<TOpaque>, 'origin'>
 
 /**
  * A basic HTTP/1.1 client, mapped on top a single TCP/TLS connection. Pipelining is disabled by default.
@@ -20,12 +20,12 @@ export class Client extends Dispatcher {
   readonly stats: TClientStats
 
   // Override dispatcher APIs.
-  override connect (
-    options: ClientConnectOptions
-  ): Promise<Dispatcher.ConnectData>
-  override connect (
-    options: ClientConnectOptions,
-    callback: (err: Error | null, data: Dispatcher.ConnectData) => void
+  override connect<TOpaque = null> (
+    options: ClientConnectOptions<TOpaque>
+  ): Promise<Dispatcher.ConnectData<TOpaque>>
+  override connect<TOpaque = null> (
+    options: ClientConnectOptions<TOpaque>,
+    callback: (err: Error | null, data: Dispatcher.ConnectData<TOpaque>) => void
   ): void
 }