Menzel recreated her Broadway role of MAUREEN in the movie musical and knew she'd have to recreate the mooning scenes that helped to win her Diggs.
But, a decade after appearing on stage in Rent, Menzel worried that her bottom wouldn't look as good as it did and she feared the big screen would make it look huge - so she asked Dawson's mum to make sure she looked butt-lovely at all times.
She says, "I lost a little weight and I was cool about the scene. I also had Rosario's mother on butt patrol.
"I said, `Make sure it looks right when I pull my jeans down and nothing is scrunching up funny. You let me know because you know those guys are gonna say it looks fine but you tell me if it's not cool.'
"I told her to tell me if it doesn't work and said, `I'm gonna tell CHRIS (COLUMBUS - director) the angle is weird and I want to do it again.'"