Depp and Graham at Venice Fest

V E N I C E, Italy, Sept. 7 -- "Any excuse to smoke I guess," said a long-haired Johnny Depp of getting into his role in From Hell as an opium-addicted 1888 London detective tracking Jack the Ripper.

The thriller from director-brothers Albert and Allen Hughes received its world premiere at the Venice Film Festival out of competition. It's based on a popular, graphic novel and suggests a JFK-style conspiracy theory as to who the Ripper really was.

Depp, who was wearing his "security blanket" — a 20-year-old hat he bought at a Florida Burdine's department store — said, "I thought [smoking was] important for the character I play. From my point [of view] he was a damaged guy [with] a lot of demons, and it was important to explore the vices he might have — drug abuse and his addictions and his demons — as well as to search for the killer."

Fans of the Topic

For the star of Sleepy Hollow and Edward Scissorhands, getting the chance to be in a Jack the Ripper movie is the culmination of a youthful obsession. "I was always fascinated with the Jack the Ripper story and the different theories, and some are very valid and solid. This is one of the more interesting, the conspiracy theory."

Depp's co-star, Heather Graham, admitted her favorite Jack the Ripper movie is the time-traveling Time After Time, in which the Victorian-era murderer is tracked by H. G. Wells into the present."I love that movie," said the actress, who studied with a dialogue coach for her role as an endangered Irish prostitute. It's the first time the star, best known for her roles in Boogie Nights and Austin Powers: The Spy Who Shagged Me, has adopted an accent in a film.From Hell opens in the U.S. on Oct. 19.