will.i.am has thanked Britney Spears for trusting his "instincts" when the pair collaborated.

The Black Eyed Peas singer wrote a track for the star, 'The Big Fat Bass', during a flight from Japan to Los Angeles, and thanked her for allowing him to have a free reign in creating the song.

He tweeted: "Thank you Britney for collaborating it was a pleasure working with you. Thank you for trusting my instincts. You're a doll. I hope your Britney army likes it as much as we do."

The duo also worked together on another track for Britney's upcoming 'Femme Fatale' album, which he recently described as "a banger".

will tweeted: "In the studio with @britneyspears today. We recorded another song for #femmefatale. that's 2 bangers (sic)."

However, the rapper isn't the only star keen to collaborate with Britney, as Nicki Minaj recently admitted the 'Womaniser' hitmaker is the only other artist she would consider working with.

She said: "I'm done with collaborations. No more collabs for the next two years. Although, Britney's a snatch like me and she's cute. Yes. We might do something."

'Femme Fatale' will be released on March 29.