Donnie Brasco (1997) - Rotten Tomatoes

Because he was so convincing in his undercover persona, the Bonanno family was seriously considering "making" Joe Pistone (fully initiating him into the mob) before they learned he was an FBI Agent.

True story of FBI agent who infiltrates the mob as Donnie Brasco

Al Pacino picked his sunglasses out himself. Mike Newell said that he has a great eye for costume.

Donnie Brasco Mike Newell, 1997 Amazon

According to Paul Attanasio, Johnny Depp's 1994 arrest for destroying a hotel room helped him get cast. People thought he was "dark and dangerous."

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Joe Pistone practicing on the FBI's firing range was inserted at the insistence of the studio, which wanted a shot of Johnny Depp firing a gun for the movie's trailer.

In this film, Al Pacino has a pet Lion. In Scarface (1983), he had a pet tiger.
Alec Baldwin, Nicolas Cage, and John Cusack were considered for the role of Donnie Brasco.

Donnie Brasco (Extended Cut) - IGN

Director Mike Newell recalled that the first scene Pacino and Depp had together was a scene in a car where they discuss 'Lefty' possibly getting out of the mob at 'Pistone's' suggestion. During several takes, Depp would fart very loudly, ruining the scene and causing Pacino to become increasingly angry with Depp. Eventually, Depp reached under his seat and pulled out a whoopee cushion that he had been using. Pacino broke up laughing and Newell realised it was Depp's intention to break the ice and tension between the actors and the two stars subsequently had a close relationship and friendship for the rest of the shoot.

Johnny Depp spent months with the real Joseph D. Pistone before shooting. Most of the time, they lifted weights together.

Al Pacino Retrospective – Donnie Brasco - Flickering Myth

Michael Madsen impulsively proposed to, and married, DeAnna Madsen during a two-day break in filming. According to Michael Madsen, Al Pacino was disgusted by his impulsiveness. The Madsens remain happily married.

Al Pacino had quit smoking by the time filming began, so he smoked herbal cigarettes. Mike Newell said they smelled awful.

Donnie Brasco - Topic - YouTube

According to Mike Newell, Lefty's leisure suit always got a big laugh from audiences. Al Pacino's clothes show that he's a little "no account guy that thinks he's a big deal."