Jared Leto Says Al Pacino Initially Didn't Recognize Him in Character on the House of Gucci Set

Al Pacino couldn't even recognize Jared Leto on the set of the much-anticipated film House of Gucci.

In an appearance on The Tonight Show with Jimmy Fallon on Tuesday, the 49-year-old actor shared the story of a hilarious encounter between the two on the set of House of Gucci.

In the film — which chronicles the murder of Maurizio Gucci, which was orchestrated by his ex-wife, Patrizia Reggiani — Leto transformed to portray Italian businessman Paolo Gucci. Pacino stars as Aldo Gucci, who was the eldest son of Gucci founder Guccio Gucci.

Leto said the first day of filming, he showed up while costumed as Paolo and greeted Pacino, 81, with an Italian accent.

"I showed up for the first day of work in character and I went up and said 'papa,' you know, papa in an accent, and he looked over and said 'papa', and he looked over and kind of just skirted away from me," said Leto, drawing laughter from the crowd and Fallon.

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"I said, 'Oh, maybe he is a little grumpy, I don't know.' I said, 'papa, it's me Paolo,' and he basically shuffled off again like, 'Who is this creep?' "

Eventually, someone on the set whispered in Pacino's ear that the mystery man was, in fact, Leto.

"And he turned around, he said 'Oh, my son! My son!' " said Leto.

MGM Studios

In addition to Leto and Pacino, House of Gucci stars Lady Gaga and Jeremy Irons, Salma Hayek, Reeve Carney, Jack Huston and Adam Driver.

The film was directed by Ridley Scott and is based on the Sara Gay Forden book, The House of Gucci: A Sensational Story of Murder, Madness, Glamour and Greed.

Leto also opened up about what it was like to work with Scott, who he called one of the "best directors in the world."

"He can do anything, from alien, gladiator, to the martian," he said speaking about Scott. "The guy just made some of my favorite films of all time."

The Tonight Show Starring Jimmy Fallon

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Leto also opened up about the Gucci family dynasty and why people should see the movie in theaters this month.

"I do have a lot of people coming up to me really interested in seeing this film. I didn't know the story of the Gucci family. I am sure a lot of people out here don't know the story of the Gucci family and it is shocking," he said.

"It's a shocking story about this dynasty. It is just Machiavellian and Shakespearean and all the ends. It is an amazingly complex story and I am really proud to be part of it."

House of Gucci premieres in theaters on Nov. 24.