Britney Spears Wonders: 'What If I Just Blank Out' In Vegas?

Spears will take fans inside 'Piece of Me' residency during her new doc, 'I Am Britney Jean,' premiering on E!.

Britney Spears is giving it her all in the sneak peek at her upcoming TV documentary. The singer will kick off her two-year Las Vegas residency, "Piece of Me," at Planet Hollywood in just two weeks, and in the new trailer for her upcoming E! special, "I Am Britney Jean," the singer is grinding hard to put the finishing touches on the show.

With her entire team of managers, choreographers and dancers wondering if the show will be perfected by opening night, Spears grinds away in dance rehearsals for the Sin City residency, which will not only include tracks off Britney Jean, but also from her massive catalog of hits.

"Couldn't do rehearsals the next day, I just knew I'd, like, almost broke my neck or something," Brit shares in the trailer for the two-hour special, airing on E! on December 22. "There was serious damage." Fans will learn just what happened to Spears later this month.

Spears also seems pretty anxious to see if she can pull off the massive stage show. "I'm really nervous. What if I just blank out and just stand there?" the femme fatale wonders ahead of the December 27 opening night.

If you think that all seems juicy, Spears dished that she just saw a first cut of the final version of the doc and that she is "excited for y'all to see it." We wonder what other confessions have made it into the special.

Spears, who revealed that she just started rehearsing on site for the gigs on Thursday, first announced plans for her residency back in September. The show will span her 15-year career and, from the sounds of it, will be quite the feast for the eyes.

"Every time I do a show, I like to bring it. I love to be really entertained," she shared in September. "Coming from the show aspect and coming from theater, I love to really put on a show, so we're going to have all the works ... there's going to be snow, water, rain, everything."

VMAs 2018