It's been revealed that Kanye West got the mainly-active-in-the-'90s pop trio Wilson Phillips (a group made up of Beach Boy Brian Wilson's daughters) to contribute their vocals for the backing on Rihanna's 'FourFiveSeconds', which already featured Sir Paul McCartney. It's a veritable supergroup.

Apparently West told Carnie Wilson, "When I think of authenticity and I think of angelic, I think of you."

Speaking to Billboard, Wilson then went on to describe Ye's demeanour in the studio:

"He was really shy and he would just smile and he's real soft-spoken, then all of a sudden when he started playing all these songs, he was dancing around the room. It was just like how Michael Jackson used to be. When he would press play, it was like, out came the artist and the creativity was just really there."

Use your ears and see if you can hear the mystery singers on the bridge and the chorus (basically, at any point where you can hear more than one voice).