'Till The World Ends' beauty Britney Spears is set to kick off her residency in Sin City on December 27 and the show's director has revealed that she is unable to contain her enthusiasm for the first rehearsals. 

Baz Halpin, the director of Spears' Vegas stage show, confessed to Billboard that he has never seen an artist so excited about a project and he can't believe the energy she's bringing to the production: 

"I'm almost having to hold back the floodgates, because she wants to start rehearsing right now. I've never seen an artist so pumped and excited. She's been doing religious vocal and choreography for months and months. So I'm waiting for this unleashed furry of rehearsal energy when we get started."  

Her manager, Larry Rudolph, also confirmed that Spears will be performing live throughout the extensive run of shows and has been in intense vocal training to prepare herself for them:

"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."