Madonna and Britney Spears are planning an explosive dance routine to ensure her forthcoming comeback world tour kicks off with a bang.

The Queen of Pop is expected to appear as a surprise guest on Spears' upcoming Circus tour later this year. The Toxic hit-maker joined her mentor Madonna on-stage in Los Angeles in November during the U.S. leg of her Sticky & Sweet tour, and the Material Girl is reportedly desperate to return the favor. 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.

A source tells Britain's Daily Mail, "When Britney joined Madonna on stage for her Sticky & Sweet tour it was very sedate. This is going to be a high-energy dance routine - getting back to what they are both good at: Performing."

Madonna and Spears shocked fans when they puckered up for an on-stage kiss during their performance at the MTV VMAs in 2003. They also teamed up on a track, Me Against the Music, the same year.

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(This news article provided by World Entertainment News Network)