A really funny story I heard was from director Stanley Donen. He directed some classic films but he also directed a cheesy science fiction film called Saturn 3 in the early 1980s. While filming Saturn 3 Kirk Douglas, who was the lead, kept bugging him about doing more nude scenes in the film. Kirk, who was still in great shape, wanted to doff his kit as often as possible in the film. So pretty much any scene they were shooting Kirk would ask him, "Wouldn't this be better if we played this nude?" and Donen would have to stop and talk to Kirk about keeping his clothes on. 

Now, it should be pointed out that his co-star in the film was Farrah Fawcett, and so, I will admit I loved Farrah as much as any guy did back then, and sure, I'd be happy to do nude scenes with Farrah as well. Thing is Kirk asked about doing every scene nude whether Farrah was in it or not. Kind of funny that Mr. Full Monty himself, Harvey Keitel, was the third lead in this. I think Harvey stays dressed in the film. 

Donen claimed it was his experience that as actors and actresses aged back then they became more interested in appearing nude. He claimed though that Kirk was always very eager to take his clothes off. He apparently did insist on doing some nude scenes in other films as well asking the same question "What if I played this nude?"

People have joked that Keitel also insists on scenes he can appear naked in but I think Keitel, when I have seen him speak, seems so serious about his craft that I don't think he would do that but who knows. Donen, I think joked that Saturn 3 was not very good because he spent a small portion of his time directing and the rest of his time trying to convince Kirk to keep his clothes on.