Britney Spears & Madonna Reunion Hit By Technical Problems

Britney Spears' video appearance for Madonna's upcoming 'Sticky & Sweet' world tour has been derailed thanks to technical problems.

Madge had reportedly asked her old kissing buddy to make a promo that would air during her stage show, in a bid to help the troubled star resurrect her own singing career.

But the troubled singer's scheduled recording slot on Tuesday was derailed as the set for the top secret video was not completed in time.

The set features an elevator on which Spears will perform, a source tells E! News online.

The insider adds, "The video will be very deep. You've never seen Britney like this before. It will blow your mind."

Madonna's publicist Liz Rosenberg confirmed Spears will record footage for the tour, but insisted the details of her appearance are "a secret".