Britney Spears and Madonna by Kevin Mazur/ WireImage.com Britney Spears and Madonna by Kevin Mazur/ WireImage.com

It took five years, but Madonna and Britney have finally formulated a follow-up to their infamous MTV Video Music Awards lip-lock.

Spears this week is participating in a music video that will serve as a major set piece for Madge's Sticky & Sweet tour, kicking off next month in Wales and hitting the States Oct. 4 (in East Rutherford, N.J.).

Thus far, details on exactly what Brit's bit will entail are being kept under wraps. (Were all her bits kept under wraps.) - Matt Mitovich