diff --git a/submodule.go b/submodule.go
index 67e4fab..20fcbe9 100644
--- a/submodule.go
+++ b/submodule.go
@@ -342,7 +342,5 @@ func populateSubmoduleUpdateOptions(ptr *C.git_submodule_update_options, opts *S
 	populateCheckoutOpts(&ptr.checkout_opts, opts.CheckoutOpts)
 	populateRemoteCallbacks(&ptr.remote_callbacks, opts.RemoteCallbacks)
 	ptr.clone_checkout_strategy = C.uint(opts.CloneCheckoutStrategy)
-	if opts.Signature != nil {
-		ptr.signature = opts.Signature.toC()
-	}
+	ptr.signature = opts.Signature.toC()
 }