Part of the pop star's set collapsed prior to her show at the baseball park, which featured guest spots from Justin Timberlake and Britney Spears, and she almost told her celebrity pals to stay away.

Chatting with Spears backstage as the two pop icons planned to perform together, Madonna told the Toxic singer, "I lost half of my stage and I was considering not doing the show; the whole lighting rig fell and I have a screen with video projection and it fell.

"If I can't do it 100 per cent I don't wanna do it at all, but there was no way to make it up. The show must go on."

The candid backstage chat was caught on camera for Spears' MTV documentary Britney: For The Record, which debuted on Sunday night (30Nov08).

In a brief interview about Spears, Madonna told MTV cameras the younger star had "a certain fragility about her and vulnerability about her that makes me feel maternal towards her."