Getty ImagesThere are only seven days left until Britney Spears begins her two-year Las Vegas residency.
And there are only two days left until E!'s two-hour Britney Spears documentary, I Am Britney Jean. Coincidence? We think not. Actually, we know not: The documentary is all about Britney's road to Vegas and features an exclusive behind-the-scenes look at her Piece of Me rehearsals.
There are a few things every Britney show needs: Dancing (Britney says her new show is the most dancing she's ever done), good music (luckily, Britney has some of the greatest greatest hits around) and fabulous costumes.
As we wait with bated breath to see what Britney has in store for us with her Vegas gig—and especially what she'll wear—let's look back at her best costumes on past tours, from the …Baby One More Time Tour days to Femme Fatale.
Spoiler alert: It's a lot of catsuits!
For even more on Britney Spears, including unprecedented inside looks at her most intimate moments and rare candid interviews with the pop superstar herself, tune in to E! News' exclusive two-hour movie event, I Am Britney Jean, airing this Sunday at 9 p.m. on E!
PHOTOS: Check out all of Britney Spears' best concert costumes!