Sir Paul McCartney didn't want his new album to sound "old-fashioned".
The Beatles legend has tried to be more experimental with his comeback album 'New' and sought to inject a contemporary, youthful feel into the record.
He told The Sun newspaper: "I wanted something that didn't sound old-fashioned. I wasn't prepared to go as far as a Katy Perry bass-drum pop sound - even though I think she makes good records. But there was an endeavour to make it sound at home in the contemporary scene."
Paul was looking for a current chart-topping producer to help him in the studio, but liked them all so much he ended up working with four.
He explained: "I didn't really have an idea who I would be working with but I had been watching the scene. Ethan Johns had done Ryan Adams and Kings Of Leon and I knew I liked what he'd done there.
"I knew Mark Ronson had done Amy Winehouse as well as a lot of other good records. I knew Paul Epworth had worked with Adele and I knew Giles Martin from his work on The Beatles 'Love' album.
"It was like having all four of them on shuffle. It kept it really interesting and I never knew quite what was going to happen next. And it certainly wasn't boring."
The 71-year-old singer is amazed he can still draw a big crowd these days and is appreciative of his different generations of fans.
Paul laughed: "Being in The Beatles was phenomenally special but we could have been dead and gone long ago and people wouldn't remember this strange little group from Liverpool.
"Then what happens is you find an awful lot of people doing the Wings sign in the audience, so there's that generation too. It's pretty amazing to still be there making new music alongside that legendary reputation."