Sir Paul McCartney has written songs for the animation film 'High in the Clouds'.

The former Beatles star is producing the movie, which is based on a children's book of the same name which he co-wrote ten years ago, and will also lend his voice to one of the characters while Deadline previously reported that he had written seven or eight songs for the animated creation.

The soundtrack for the film is to feature a collaboration between the 'Four Five Seconds' hitmaker and Lady GaGa, who first sparked rumours she was working with Paul on an Instagram post back in February.

The post read: ''Always a good time with my buddy. I'll never forget when he called me last year to work and I hung up the phone cuz I thought it was a prank!(sic)''

The 72-year-old star previously spoke about his excitement at being part of the team bringing the project to life.

He said: ''High in the Clouds is a passion project for me. I am thrilled to be working in partnership with Randa Ayoubi and David Corbett at RGH, and David Michael Lynne and Bob Shaye of Unique Features. Working with the highly creative talent at these companies together with Josh Klausner and Tony Bancroft, we will be able to create a warm, funny and moving animated film that will resonate with worldwide audiences.''

Meanwhile, Pearl Jam guitarist Mike McCready is also said to have contributed his musical talent to the upcoming project.

'High in the Clouds' will be directed by 'Cloudy with a Chance of Chance of Meatballs 2' filmmaker Cody Cameron and 'Date Night' screenwriter Josh Klausner.

A release date is yet to be announced.