Michael Buble, Simon Cowell and Ashley Roberts stunned revellers in a London bar on Saturday night (30Mar13) by taking over the establishment for a U.K. Tv show.

The trio, along with racing driver Lewis Hamilton, appeared on Ant MCPartlin and Declan Donnelly's Saturday Night Takeaway series and ended the episode by heading to a nearby pub.

Canadian crooner Buble sang his new song It's A Beautiful Day as he crossed the road from the Tv studio to the bar, where the former Pussycat Dolls star served as a barmaid.

Music mogul Cowell was seen sipping a drink and Buble then rapped a few lines of the presenters' hit track Let's Get Ready To Rhumble on the karaoke.

The song, recorded under the duo's pop alias Pj & Duncan, topped Britain's singles chart on Sunday (31Mar13) nearly a decade after its original release in 1994.