Washington, Jan 5 : Both the queen and princess of pop, Madonna and Britney Spears, are planning an explosive dance routine for the Toxic singer's upcoming comeback world tour.

Madge is expected to appear as a surprise guest on Spears'' upcoming Circus tour later this year, and she is reported to be very eager to return the favour that Spears had showed on her Sticky + Sweet tour.

Spears has reportedly hired Jamie King, the choreographer of Madonna''s last three tours, to create a high-energy routine the duo can perform together.

"When Britney joined Madonna on stage for her Sticky + Sweet tour it was very sedate," Contactmusic quoted a source as telling Britain''s Daily Mail.

"This is going to be a high-energy dance routine - getting back to what they are both good at: Performing," the source added. (ANI)