Sir Paul McCartney originally just wanted one producer to feature on his upcoming album.
The 'Hey Jude' singer has been working with a host of big name creators on the follow-up to last year's 'Kisses on the Bottom', including Mark Ronson, Paul Epworth, Ethan Johns and Giles Martin, but he admits he was blown away by the individual twist they each had which is why he chose to have all four of them on the studio collection.
Speaking to Zoe Ball on BBC Radio 2 this morning (29.08.13), he said: "The album is quite varied, but the thing is, the songs are quite varied anyway and originally I was just going to do maybe one song with each producer just to see who I got on with best, but I ended up getting on with them all and really liking the individual thing they brought to each song.
"So I did a few songs with each of them but they're all really cool guys and they've all done really great work. They've each had a different approach."
The 71-year-old star released the title track from his latest album, 'New' and gave a preview of his work this morning (29.08.13).