[Harry!]

http://www.showbizspy.com/article/18...spears-on-tour

Madonna is rumored to be joining Britney Spears on tour.

Spears, 27, kicks off The Circus Starring Britney Spears, which will take in 31 US cities, in New Orleans today (March 3).

And Madonna - who recently announced a series of European dates for the 2009 leg of her hugely successful Sticky & Sweet tour - is reportedly set to join the Toxic hitmaker on stage during some of her shows.

A source says, "The rumor going around is that Madonna is going to join Brit onstage for at least two tour dates.

"And that would be totally fierce."

Spears' manager Larry Rudolph said Tuesday her tour will be "intense".