Britney Spears was advised by MTV to rehearse and rest during the last couple days before her long anticipated Video Music Awards comeback performance, Daily News reported.  

"Britney knows she's on thin ice. When they agreed to the performance, they sat her down and told her she should not be going out, and instead focus on rehearsing and resting," an insider was quoted by the Daily News as saying. "She seemed to be thankful and appreciative for the chance, but who knows with her? MTV made it clear that her usual behavior will not be tolerated."

A video of a well behaving Britney emerged online showing her on a stage surrounded by dancers while rehearsing. However, that’s not all she’s been doing since her arrival in Las Vegas, where the MTV Music Awards ceremony will take place Sunday night.
According to perezhilton.com, the mother-of-two was spotted out early Friday nigh at Body English in the Hard Rock Hotel before heading over to Diddy’s party at Pure in Caesar’s.

As far as Saturday night is concerned, Britney was seen at the Mystere by Cirque du Soleil show at Treasure Island in Vegas with some friends.

MTV confirmed Britney’s intensely speculated VMAs performance last week revealing that she will play live her new single "Gimme More" in the opening act, which will also involve illusionist Criss Angel.

"You can expect the things we want and expect from Britney, that will all be there," Jesse Ignjatovic told MTV.com. "What I've seen of it is great. She'll be dancing, performing, doing her thing. That's exactly what we all want. Fans that are familiar with her performance on previous VMAs will not be disappointed.

"She'll kill it," he said. "She'll captivate everyone, and set the tone for the rest of the night. There's no one better."

According to MTV President Christina Norman, tonight’s show is going to be a "one-of-a-kind, must-see, one-night-only event."