Lady GaGa is working with Sir Paul McCartney.

The 'Do What U Want' hitmaker has shared a photo of herself in the studio with the former The Beatles star, and revealed she originally hung up on him when he called her to propose the idea of collaborating because she thought it was someone playing a joke on her.

Along with a photo of herself and the iconic musician next to a drum kit on Instagram, she wrote: ''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 28-year-old musician is currently making the follow-up to her third solo studio album 'Artpop', which was released in 2013, and has been working with the 'Let It Be' singer as well as Disco producer Giorgio Moroder.

Another photo posted on her Instagram account also sparked rumours of a collaboration with Adele recently, as it showed the pair hanging out in Los Angeles online.

Meanwhile, Sir Paul has been busy working with other musicians as he features on Rihanna's new single 'FourFiveSeconds' which he will perform at the Grammy Awards on Sunday (08.02.15), as well as Kanye West's emotional track 'Only One' which is about the 37-year-old rapper's 19-month-old daughter, North.