Donatella Versace likes her models to be "real men".
He told Vogue.com: "When I went for my first casting with Donatella she said to me 'I want real men to do my campaigns.'
"I think music has a lot to do with which models are seen as in fashion. If you look at the 90s, when skinny male models were really in, the music was Nirvana and Oasis - and models looked like the boys that were in those bands. Music's changing and so is modelling. I think having really skinny guys keeps a lot of people out of the market. You want an image that will really sell clothes."
Paul - who has previously dated A-list actress beauties Cameron Diaz and Jennifer Aniston - is normally confident surrounded by beautiful Women, but says he was so taken aback by the way Naomi Campbell introduced him to Christy Turlington he had to make an excuse and leave.
He added: "All the models I've worked with are lovely in their own ways but I think Christy Turlington is stunning.
"I was on a shoot with her and Naomi and I told her how gorgeous I thought she was and she said 'I'd better introduce you then.
"She went straight up to Christy and said 'This is Paul, he thinks you're pretty' then walked off! I was so embarrassed I can't tell you. I didn't really know what to say so I sort of said I needed the loo and ran off."
Paul has recently turned his hand to acting, and his debut film 'Di Di Hollywood' is out now.