The Sony/ATV-signed composer, real name Nadir Khayat, is famous for his work with GaGa - helping to pen her UK number one hits Bad Romance and Just Dance, as well as her recent Top 10 singles Judas and Alejandro.

And in an exclusive interview with Music Week, RedOne said the two performers would appear together on one of the album's tracks.

"It's a track that GaGa and I wrote together a while ago and when Cher heard it she just ...