diff --git a/cmd/kubeadm/app/cmd/completion.go b/cmd/kubeadm/app/cmd/completion.go
index 22067ade00a..7c3d3090a8b 100644
--- a/cmd/kubeadm/app/cmd/completion.go
+++ b/cmd/kubeadm/app/cmd/completion.go
@@ -122,7 +122,7 @@ func RunCompletion(out io.Writer, boilerPlate string, cmd *cobra.Command, args [
 	}
 	run, found := completionShells[args[0]]
 	if !found {
-		return errors.Errorf("unsupported shell type %q", args[0])
+		return errors.Errorf("unsupported shell type %q, the supported shell types are %v", args[0], GetSupportedShells())
 	}
 
 	if len(boilerPlate) == 0 {