Clement has worked closely with the former Manchester United midfielder to get his match fitness up to standard.
"Anyone who thinks he's just here for shirt sales isn't all there," Clement told the Guardian. "Watch him in a game and see his competitiveness, winning tackles, getting stuck in. He's not flying up and down the right, whipping crosses in on the run, but he's at an age where he understands what he can contribute, like Ryan Giggs at Manchester United.
"I'd never met him before but, because his life has been lived so publicly, it was almost as if I knew him when he signed. But what a professional. What a gentleman."