John Cazale, an actor among actors

If you ever want to stump your movie geek pals with a barroom bet, just ask them who's the actor who appeared in only five feature films and all of 'em -- that's right, all five -- earned an Oscar nomination for best picture. The answer: John Cazale, the peerless '70s-era character actor best known for playing Fredo in the first two "Godfather" classics and also appearing opposite Al Pacino in "Dog Day Afternoon," opposite Gene Hackman in "The Conversation" and in the great ensemble of actors who brought "The Deer Hunter" to life.

Cazale had a brief, meteoric career, dying of cancer at 42 in early 1978, before "The Deer Hunter" made it to theaters. A solitary artist who honed his craft in off-Broadway stage productions, Cazale was the kind of intense perfectionist who'd probably be making his living in Sundance films. So it's appropriate that the first documentary about the actor is premiering at Sundance today in the U.S. documentary shorts competition category. Directed by Richard Shepard, the writer-director of "The Matador" and "The Hunting Party," it's called "I Knew It Was You," after a memorable line of dialogue from "Godfather II."

The film is a must-see, if only to soak up Cazale's devotion to his craft as well as to watch interviews Shepard did with nearly all of the actor's most important collaborators, notably Pacino, De Niro, Hackman, Francis Ford Coppola, Sidney Lumet and Meryl Streep, who fell in love with Cazale after playing opposite him in a 1976 production of "Measure for Measure" and took her part in "The Deer Hunter" largely to be near Cazale, who by then was already battling cancer.

The movie is a delight as a historical document, but it also serves as a way of reminding younger actors of Cazale's potent abilities: Shepard also features interviews with a trio of today's great acting talent -- Philip Seymour Hoffman, Sam Rockwell and Steve Buscemi -- who talk about Cazale's influence on their work.

"If John were a baseball player, he'd be in the Hall of Fame," Shepard told me the other day. "But even though he was always my favorite actor, there was nothing on the Internet about him except one article in Entertainment Weekly. I mean, if you get Quinlan's Character Actors, this gigantic 900-page book on character actors, he's not even in it."