will.i.am asked for Sir Mick Jagger to appear on his new single as he thought it would "never be possible".
The Black Eyed Peas singer was tired of being asked of who would guest on his songs, so picked the most unattainable person he could think of to target for his new track 'T.H.E. (The Hardest Ever)' - which backfired when he agreed to do it.
will.i.am told RollingStone.com: "I went to play material for the label and [Interscope label head] Jimmy Iovine's like, 'Yo, this is dope. Who are you gonna put on it?'
"I'm like, 'What are you talking about? It's finished, it's me.' So, he's like, 'Oh, you don't feature no-one?'
"You play your music and the first thing someone says, 'Who's gonna be on it?' So I think of the hardest thing ever. And it happened, Mick Jagger. I just wanted to throw something out there that I thought could never be possible so they would stop asking me."
will.i.am was astounded when The Rolling Stones frontman agreed to appear on the song and even got Jimmy - who started his career as a record engineer and produced albums for U2 and Stevie Nicks - to record the vocals.
He added: "Jimmy's like, 'Mick Jagger and the Rolling Stones are like my Tribe Called Quest, my De La Soul, my N.W.A. I wanted to be like Mick when I was young,'
"He produced Mick's vocals, and this was the proudest moment of my life. Winning a Grammy is cool, but the guy who helped you out - and then you got to see him execute one of his dreams - that's just the dopest ever."
will.i.am will release his fourth solo record '#willpower' next year while Black Eyed Peas are on hiatus.