will.i.am leaks Britney track

will.i.am has leaked a snipped of 'The Big Fat Bass', a new Britney Spears track he's been working on.

The track, which is set to appear on Britney's 'Femme Fatale' album, can be heard here.

He posted the snippet, plus a note addressed to Britney which said: 'Thank you Britney for collaborating it was a pleasure working with you. Thank you for trusting my instincts. You're a doll.

'I did this little art my self on my Mac,' he continued 'I made it on the plane from Japan to LA...I hope your Britney army likes it as much as we do.'

'The Big Fat Bass' is the fourth leak from the album. Co-executive album producer Dr Luke has already leaked snippets of 'Inside Out', 'I Wanna Go' and 'How I Roll'.