Leonardo DiCaprio's transformation into J. Edgar Hoover, the longtime director of the F.B.I., required hours in the makeup chair. Keith Bernstein / Warner Brothers Pictures

For an actor who takes risks, the risk of becoming boring.

Los Angeles

To transform himself into an aging J. Edgar Hoover, Leonardo DiCaprio sat for hours while makeup artists gave him liver spots, yellow teeth and a bulging stomach. He spends a good chunk of Clint Eastwood's film "J. Edgar" that way.

He also memorized endless rapid-fire monologues. And he had to wrestle with a man, then kiss him. And wear a dress.

Mr. DiCaprio has made a career of highly risky choices, and somehow it keeps paying off.

"When I can't immediately define the character, and there's an element of mystery to it and still a lot to be explored, that's when I say yes," Mr. DiCaprio said. "I like those kinds of complicated characters. I just do."

Hollywood typically doesn't like that answer. "The apparatus likes to box actors up," said Brian Grazer, a producer of "J. Edgar," set for release on November 9 in the United States and worldwide this winter. "Once they become successful in one role, get them into picture after picture where they can do exactly the same thing." He added: "Most people are too afraid."

It probably helps that Mr. DiCaprio, 36, has managed to retain a mystique about his personal life. Keeping that distance is something he works on. He has his own version of sticking with what works. The characters are mostly tortured, unsympathetic, larger-than-life: A urine-collecting Howard Hughes in "The Aviator." A Zimbabwean smuggler in "Blood Diamond." A mental patient in "Shutter Island." A dream extractor in "Inception."

"When I can't immediately define the character, and there's an element of mystery to it ... that's when I say yes." Leonardo DiCaprio with Clint Eastwood on the set of "J. Edgar". Keith Bernstein / Warner Brothers Pictures

In "J. Edgar," Hoover is depicted as a brilliant patriot who invented modern forensics and stopped at nothing to protect America through eight presidents and three wars. But the omnipowerful F.B.I. director was an impediment to the civil rights movement and worked as hard to distort the truth as he did to collect it to secure his power.

Was Hoover homosexual? Nobody knows for sure. Even less clear is whether he liked to wear women's clothes, but Mr. Eastwood retains a nod to the rumor.

Some in Hollywood fear that Mr. DiCaprio will become uninteresting to audiences if he doesn't take on a wider variety of roles.

Does he worry about boxing himself in by trying to stay out of the box?

"Never. No. I don't," he said.

Mr. DiCaprio has three Oscar nominations, for "What's Eating Gilbert Grape," which he made when he was 19, "The Aviator" and "Blood Diamond."

He lit up when talking about movies and people that have influenced him, particularly Billy Wilder's "Sunset Boulevard." But personal questions are not appreciated. Just why is it that he dates all those supermodels?

"I've never really talked about that kind of stuff, and, very respectfully, I'm going to keep it that way," he said.

He'd rather stick to "J. Edgar," particularly that prosthetic makeup. He estimates that he spent about two weeks of the 39-day shoot as "old Hoover," which required sitting up to five hours a day in the makeup chair. "To stay in character and to fight the urge not to rip it off at times and to not feel trapped inside it is extremely hard," he said. "It's like you've been slathered in honey and wrapped in a giant duvet."

He did months of research to be able to inhabit Hoover fully. "The research of these roles is half the fun and half the challenge " maybe more," he said.

Dustin Lance Black, who wrote the "J. Edgar" screenplay, said Mr. DiCaprio dug up films of a young Hoover giving speeches. "Hoover liked to weave a lot of allusions of slimy, slippery animals into his speeches at that time," he said. "Leo loved it. He said, 'Come on, we've got to use this stuff.'"

(Mr. Black also remembers Mr. DiCaprio's fondness for German chocolate cupcakes. "Some of those pounds on later Hoover were not prosthetic," he said. "I'll say it. Leo got a little fat.")

It is unclear whether "J. Edgar" will be a hit, but Mr. DiCaprio has an insurance policy in that ever pesky "Titanic," first released in 1997, which will be rereleased in April in 3-D. He said he had come to terms with being associated with the dopey Jack Dawson.

"I've been to the Amazon," he said, "and people with no clothes on, and I'm not exaggerating, know about that film. I've accepted it."

The New York Times