Robert De Niro talks embodying his "mythological" gangsters in The Alto Knights, whose real conflict inspired The Godfather

The Alto Knights is a gangster story that revolves around two larger than life figures: Frank Costello and Vito Genovese. Both were at different times known as the 'Boss of Bosses' in the American Mafia, and, in The Alto Knights, they're both played by Robert De Niro.

"A lot of the history of what they actually were known for, what they did, looking at videotapes and stuff, there was not as much as I thought there would have been," De Niro tells us when we meet with him in London. "But there was enough for me on Genovese and Costello – and books I'd read, many books on Costello."

Costello is actually a role De Niro almost played 50 years ago in a project with The Deer Hunter director Michael Cimino, too. "In fact, [producer] Irwin Winkler wanted to do a movie. He talked to Mike Cimino, and Cimino talked to me about the Costello character in the late '70s," he recalls.

Of course, with figures like Costello and Genovese, they cast long shadows not just in the annals of history, but in pop culture, too. "They were well known, almost mythological types of characters in those days, and things for other movies were taken off what was known about them," De Niro reflects. "I think even the drug thing in The Godfather was [inspired by them]. In this case, we have it with Genovese and Costello, and I think that might have been taken from what was known about that conflict with Costello and Genovese for the drug conflict in The Godfather, I think."

But De Niro's co-star Debra Messing, who plays Bobby Costello, the strong, capable wife of Costello, admits she wasn't an expert going into the film. "The thing that struck me was that I had never known about their relationship, and I didn't know the story, and that was really intriguing to me," she says. "And also the character of Bobby was such an atypical wife of a mafioso, that was thrilling for me."

Like De Niro, Messing threw herself into research to portray Bobby. "I read seven books on Frank Costello, and there was a lot of information about Bobby and her temperament, and how their marriage was really special in that way," she explains. "And so it really gave me the confidence to bring that strength to the role."

The Alto Knights is in theaters from March 21. In the meantime, check out our guide to all the upcoming movies of the year to fill out your watchlist, or see our guide to 2025's major movie release dates to plan your theater trips.