Britney Spears is just three months away from her two year "Britney: Piece of Me," residency at Las Vegas' Planet Hollywood, and despite rumors, she'll be singing live.

She's already told us "there's going to be snow, water, rain, everything" during the 90-minute performance, but her longtime manager, Larry Rudolph, tells Billboard there is one thing there won't be: lip-synching.

"She's going to be singing live. She does choreography and vocal coaching every day. The vocal coaching is really just to strengthen her voice and get her to a point where she can go out there every night and do a full show," he said of the show, which he says has been selling strong despite speculation that ticket sales have been soft.

Britney Spears Is 'About To Show All These Bitches How It's Done.'

"It's hard for the public to fully understand what goes on when you get onstage and you're dancing full out during a song. No matter what anyone says, there's not a single artist who goes out there and does full choreography and is singing without a vocal track underneath them at the same time," he continued. "It's physically impossible. We're just trying to build up her stamina and get her to a point where she can do as much as humanly possible. The idea is to try to get her pretty close to 100 percent. There might be some numbers where she's full out dancing with a [vocal] track underneath her, but there won't be any lip-syncing across the board on anything."

Weeks before she plays her first show on December 27, Spears will release new music on December 3. Rudolph likens this still-untitled release to Madonna's iconic 1998 album Ray Of Light. Rudolph also called her 2011 release Femme Fatale her answer to that Madge release, but Spears did end up working with Madonna's producer William Orbit on this next release, which she is still recording.

"There are a couple other songs that have a really modern EDM vibe and other stuff that has more of a Ray of Light [Madonna] vibe. I really think of this as Britney's Ray of Light album. It's kind of like that in a lot of ways. She wrote everything on the album with collaborators. There's one or two she wrote herself. That's something she wanted to do coming in. She wanted to make it very personal," he teased. "They're all custom made for her, based on what's going on with her life and in her head."

Among the "rich material" which might make the final cut of the release, which is being executive produced by will.i.am, is a ballad called "Perfume." "Britney wrote it with Sia. It's a breakup song that's about wanting the next girl to smell your perfume on the guy afterwards. The lyric is really unique and she sings the shit out of it," he said. "I think everyone will be really impressed by the song. I don't know if it will be the second or third single, but it will definitely be a single."