But as Madonna's Sticky & Sweet Tour winds down and she begins pursuing other ventures, she just might add a few dates on Britney's upcoming Circus tour to her to-do list.

OK! reports that, "Choreographers have been asked to create an out-of-this-world dance routine for Britney and Madonna... This is going to be a high energy dance routine—getting back to what they are both good at, performing."

Of course, Britney, 27, and rumors go hand-in-hand. Madonna, 50, has also been a longtime bedfellow with rumors.

Leading up to Brit's appearance at Madge's November show, stories swirled that Justin Timberlake would join the two of them for a vocal threeway.

But while JT did indeed take the Dodger Stadium stage, it was way after Spears had exited.

OK! also reported in July that Timberlake, 27, would be recording a duet with Britney on her album Circus...alas, a collaboration that never came to pass.

Can the stars align just right to allow the two most famous women in pop to get into each other's groove?

Leave a prayer for it in comments!