Britney Spears has asked Madonna to guest star on her upcoming world tour.
Britney is planning to unveil her superstar pal as a surprise guest when the pop tart kicks off her circus-themed comeback tour next year.
Britney joined Madonna onstage in Los Angeles last month during the U.S. leg of her Sticky & Sweet Tour
in November, now Britney wants Madonna to return the favor when she kicks off her first tour in nearly two years in New Orleans in March."I'm choreographing