NEW YORK—The idea of Sacha Baron Cohen taking a pivotal role in a Martin Scorsese film seems almost as unlikely as Entourage’s one-dimensional Vinnie Chase working with Scorsese in The Great Gatsby. Borat and the man behind Raging Bull?

It actually has happened, however, with Cohen playing a central character in Hugo, Scorsese’s new film about a boy whose quest to find answers after his father dies affects the lives of several people working in a Paris train station in the early 1930s.

In a New York hotel room, Cohen says he came into the project thinking he would be working on a one-man show but discovered that Scorsese is a great collaborator. “I expected him to be an auteur, and he is, but I think that part of his power and the reason why his films are so successful is that he is ready to collaborate fully with his actors. I came up with some wild ideas, like taking a bath with a dog, and he was ready to try them out. I was going through some old Chaplin and I thought, ‘Maybe there is a scene or something with a train. Maybe Asa [Butterfield, who plays the title character] gets caught in the train.’

“Marty said, ‘Let’s try it.’ I said, ‘Are you sure? It’s going to involve hundreds of extras and a moving train.’ He was totally ready to try out any idea, however ludicrous the suggestion, which was worrying to the producers. The scene was like sketch comedy, except you have 500 extras and award-winning designers and producers and actors. But it was a lot of fun for me.”

Cohen developed his character in collaboration with Scorsese. When he first got the script, the character, a security guard at the train station, seemed totally caught up in catching children and sending them off to an orphanage. Cohen felt that there needed to be a reason for his fixation so the audience would support the character in his eventual pursuit of love with a flower girl (Emily Mortimer.) He wanted to get the relationship right because it was the first time he had been given a traditional romance on-screen.

“I wanted to know why he was obsessed with chasing children. Was he a classic villain or was there a reason for his malice, and I sat down with Marty and told him I thought he might be a war veteran. We were trying to examine the roots of evil and chasing children, so we decided that he himself was an orphan and was sent to a workhouse.

“That was the only structure that he knew, and that was what he was going to impose on these children. He is dark, but he does have beauty and softness underneath him. This is the first romantic plot I have had that has not been with a black prostitute or a man. We didn’t have a kissing scene, but there was a bit of romance in there, so that was a little different for me.”

Watch the trailer for Hugo.