Chris Martin gave Queen Latifah a $150,000 piano - but she didn't know who he was.

The Coldplay frontman sat next to the 45-year-old rapper at Alicia Keys' Black Ball charity auction and they decided to bid together on the custom-made instrument used by the host on 'Empire State of Mind', her 2009 collaboration with Jay Z.

Queen Latifah recalled on 'Jimmy Kimmel Live': ''I sit next to this white guy, I don't know this guy. But he seems cool, like, he seems chill. And so, he looks like, 'Yo, you wanna get this piano?' I'm like, 'Yeah, let's start bidding!'

''So we start trying to get the room to bid on this thing. And we get it up to like $150,000 for this piano.

''So we pay this, and then I find out that the guy who I'm bidding with was Chris Martin from Coldplay.''

And after paying two thirds of the final bill for the instrument, the 'Fix You' hitmaker told the 'U.N.I.T.Y.' singer to take the piano, which is adored with an image of the New York skyline, home.

Latifah added: ''He pays $100,000 on the piano, I pay 50. He gives me the piano. He is the salt of the earth as far I'm concerned.''