Christina Aguilera and Pink's relationship started off on an icy note when the initial talks for a cover of LaBelle's "Lady Marmalade" sung by Christina, Pink, Lil' Kim and Mya for the Moulin Rouge! soundtrack started. Pink recalled the first conversation about the superstar collaboration where Aguilera reportedly walked in with label executive, Ron Fair, in her Behind the Music segment on VH1:

"Ron Fair walked in. He didn't say hi to any of us and said, 'What's the high part? What's the most singing part? Christina's going to take that part.' And I stood up, and I said 'Hi. How are you? So nice of you to introduce yourself. I'm Pink. She will not be taking that part. I think that's what the fucking meeting's about.'"

Watch her explain it at the beginning of the video above.

Rockiness factor: Tiny earthquake.