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Ke$ha said that she is 'honoured' to work with Britney Spears on her new album.
The singer co-wrote the track 'Till The World Ends', the new single from 'Femme Fatale'.
She told MTV: 'I consider myself a songwriter before and above everything else, so it's an honour to write for one of pop music's biggest icons.
'And I hope it gets everyone's ass on the dance floor 'cause y'all know that's what K-Monay does best!'
'Femme Fatale' is due out on March 28th.