WHERE ARE THEY NOW: The cast of 'The Godfather'

Al Pacino in the '70s and today.Archive Photos & Frazer Harrison / Getty

• At the time of filming, Marlon Brando was already a star, but the movie was considered his comeback. Before his death, he was known as a difficult actor to work with.
• Al Pacino was an unknown when director Francis Ford Coppola cast him as Michael Corleone. Over the decades, he has become an acclaimed actor.
• Diane Keaton was also relatively unknown at the time of filming. Today, she is one of the most successful actresses in Hollywood.

"The Godfather" has a star-studded cast, but at the time of filming, director Francis Ford Coppola wasn't so sure he had it right.

"The cast was always up in the air, and there was a lot of controversy," Coppola told Variety.

He cast Marlon Brando — a star at the time of filming — but many of the other actors were then-unknowns. That all changed after the movie premiered in 1972 and became a cultural juggernaut.

Almost 50 years since the film premiered, Insider is looking back at what the cast looked like then and what they're up to now.