Britney Spears will sing at her Las Vegas residency.

It has been claimed the 'Work Bitch' singer will only lip-sync during her two-year 'Britney: Piece of Me' shows at the city's Planet Hollywood hotel, but Kurt Melien - Vice President of entertainment at the venue - has blasted such accusations.

He told the Las Vegas Sun newspaper: ''She's in the physical shape and vocal shape to sing the entire show.

''[She is] super pumped and really excited about the show and has already been working out and rehearsing ever since negotiations began.''

The star's representative emphasised she has been working five hours a day with one of Hollywood's strongest keep-fit trainers and a vocal coach all summer to get in shape for the shows.

Kurt added: ''It will be a big Las Vegas-style production show married to a dance-club environment ... 21 of her greatest hits and some of the new music from her eighth studio album.''

Britney, 32, has previously said she will pull out all the stops for the show.

She said: ''We are going to have all the works - snow, water, rain, everything. Every time I do a show, I like to really bring it. I love to put on a show that will really entertain fans. We want the feeling that fans will be in the show with me.''

Britney had previously been criticised for appearing to mime at past concerts, but has never publicly addressed the issue.

Britney's new album will be released on December 3 while her 'Britney: Piece of Me' residency will kick off on December 27.