Tony Leung, probably the world’s most celebrated Chinese actor, had to beg Wong Kar Wai, probably the world’s most celebrated Chinese director, for a moustache.

Mr. Wong is known for his torturously long, sometimes scriptless, film shoots. Mr. Leung is known for his boyish good looks and for his role in Mr. Wong’s “In the Mood for Love” which won him the Best Actor award at Cannes in 2000.

He agreed to reprise that role in “2046,” but Mr. Wong wanted Mr. Leung to play the character as a darker, womanizing sadist. And Mr. Leung wanted a moustache.

“My character has the same background as ‘In the Mood for Love,’ the same hairstyle, the same costume, it’s filmed on the same set and because it’s Kar Wai I don’t have a script,” Mr. Leung explained. “I need something to get hold of, and I said, ‘Can I have a moustache at least?'” He got his moustache, and the role also earned him a Hong Kong Film Award for Best Actor, the fourth time he’s won with a Wong Kar Wai movie.

Their 15-year collaboration started on “Days of Being Wild” (1991) a movie set in 1960s Hong Kong. Mr. Wong’s editing eventually reduced Mr. Leung’s role reduced to a single, enigmatic closing shot. A year later, the two came together again to create “Ashes of Time” (1994) a martial arts movie that took two years to shoot in the Yuli Desert.

“For me it was very exhausting physically, and the location was very remote,” Mr. Leung said. “I was there for almost two months, and it was so boring I got drunk every day after work.” After he was finished with his part in the film, Mr. Leung returned to Hong Kong and began working on an album.

“Suddenly, one day Kar Wai called me and said, ‘Are you interested in working on another project?’ And I said yes, and he said, ‘We only have 10 days to shoot it, you don’t mind?’ It was the fastest movie ever made.” The movie was “Chungking Express” (1994), now considered a classic, and it put Mr. Wong on the international cinema map.

Their next collaboration was “Happy Together” (1997), a gay love story set in Buenos Aires, for which Mr. Leung was trapped in Argentina for a year. “Sometimes I can’t stand the shooting anymore and I don’t know what else we can shoot. We already have enough footage for a movie and still we’re shooting.”

Fans who are tired of the repressed, subtle movies Mr. Wong and Mr. Leung have made recently will be ecstatic about their next collaboration. “One day we were talking on the set and said we should do something different, at least for the audience. So why not a kung fu movie?”

Mr. Leung will play Ye Wen, Bruce Lee’s master, in a straightforward action film directed by Mr. Wong. He’s eagerly embraced a six-month training regimen, but he’s less excited by the movie’s 1960s setting, which will require him to slick his hair down with pomade again.

“I have to have this stuff in my hair again, and it is terrible,” he said. “It gets on your clothes, on your skin, on your hands. I try to wash it out every night so my skin won’t break out, but nothing works. I even tried laundry detergent. No result.”