David Bowie
Well, how about David Bowie? With CGI and makeup and a big latex schickengruber he could pass for the younger Iggy Pop, and he certainly knows enough about the subject to express Pop's hidden depths. Bowie wouldn't need to act very hard - a stunt double would do the live performance work, and when off-stage all Bowie would have to do is mumble and look baffled and wasted. Instant Iggy.