"We have a song called 'Mannequin' that we're adding to the show, which I'm really, really excited about, so it should be interesting," she told "Entertainment Tonight." "We have to update [the show] or it gets really boring."
Britney added that she's also spicing up some of her old numbers for the tour, which hits the States on August 24 at New York's Madison Square Garden and finishes in Las Vegas on September 27 before making its way to Australia in November.
"We've changed up a couple of numbers in the show," she said. "So that's going to make it a lot more fun for me and the dancers. It'll be cool."
Britney is not only hard at work on tour, but she also recently tweeted that she's back in the studio, working with an old friend. "In Stockholm in the studio with Max Martin," she tweeted.
Britney has collaborated with Martin on several of her hits, including "... Baby One More Time," "(You Drive Me) Crazy," "Oops! ... I Did It Again" and "Stronger." After not participating in Britney's In the Zone album, Martin, who has also worked with the Backstreet Boys and 'NSYNC, came back onboard for Circus, co-writing the controversial "If U Seek Amy."