NEW YORK - In a career that has included drunk pirates and a scissor-handed recluse, Johnny Depp says the strangest scene he's ever filmed is a simple flashback in "Sweeney Todd: The Demon Barber of Fleet Street."

The movie is the sixth collaboration for Depp and director Tim Burton - and one of their riskiest. It's based on Stephen Sondheim's bloody Broadway musical about a murderous barber, and Depp had scant singing experience.

But it wasn't the singing that scared Depp - or any of his character's numerous gory murders. It was a flashback to young Sweeney's happy life before he was sent to prison by Judge Turpin (Alan Rickman).

It's arguably the most normal scene in the movie, and both Depp and Burton could hardly stomach it.

"I think that was the weirdest thing I ever had to shoot," Depp said in a recent interview. "[Burton] literally was sobbing. He left the set of his own movie."

Burton said the extreme melodrama of the scene was difficult to watch.

"That's when I knew [Depp] was a great actor, because that was terrible," Burton, 49, said. "That was so bad."

Depp, 44, star of the "Pirates of the Caribbean" films and "Edward Scissorhands," has received rave reviews for his performance, and Burton wonders if the actor will look back in later years and cringe at the young Sweeney flashback.

"That and having to soap up Alan Rickman's face were two of the scariest moments, maybe of my life," joked Depp.

"Sweeney Todd," a DreamWorks/Paramount release, has received four Golden Globe nominations. They include best musical or comedy, best director for Burton, best actor for Depp and best actress for Helena Bonham Carter. *