Britney Spears is apparently in "vocal shape" for her forthcoming Las Vegas residency.

Caesars VP of entertainment, Kurt Melien, told Billboard he believes the pop princess' Piece of Me shows will include 21 of her greatest hits, as some fresh tunes from her new LP.

When asked if Spears is planning to sing live at the gigs - which are due to take place at Planet Hollywood Hotel & Casino - Melien said: "We haven't had that conversation. She certainly has been a singer and dancer her entire life, and she certainly has the chops today.

"There's no doubt about it that she's in the physical shape and vocal shape to sing the entire show. She's working out a ton, training a ton and rehearsing a ton. She's super pumped and really excited about this idea since it became real."

He continued: "It's 21 of her greatest hits, effectively, and some of the music from her eighth studio album [scheduled for release on December 3]. It's a retrospective on some of the most iconic moments of her life, combined with the more contemporary stuff that she's doing today.

"The show is going to use projection across almost all of the walls, left and right surrounding you. So it's going to feel almost like a planetarium. You're going to have this massive storyline projection around you."

Melien added that the concerts will be directed by Baz Halpin, who has previously worked with the likes of Katy Perry and Pink.

Spears will kick start her residency on December 27, and is due to perform 50 shows a year as part of her contract.