Drew Barrymore sees Grey Gardens as the chance of a lifetime, quite literally.

"I believe that I have not proven myself yet," Barrymore said of her acting chops. "Michael (Sucsy, director) taking this chance on me is one of the greatest opportunities I've ever had in my life."

The made-for-TV movie Grey Gardens, which stars Jessica Lange and Barrymore as "Big Edie" and "Little Edie" Beale, debuts tonight on HBO Canada. It's based on the famous 1975 documentary about the eccentric mother-daughter combination, and HBO Canada will air the original doc immediately following the new dramatic version tonight.

"I was scared all the time, I felt sick to my stomach, I thought I was going to die, because I felt such a responsibility to the people who loved the documentary and hold ("Little Edie") in such an intense regard, such a loyalty," Barrymore said.

"I worked harder on this than anything I've ever worked on in my life."