Robert De Niro walked into the ring forty years ago in Martin Scorsese’s Raging Bull to portray real-life boxer Jake LaMotta, and he established a new standard for film acting that Hollywood stars have strived to match ever since. De Niro, who was already known for transforming into figures like Travis Bickle in Taxi Driver and Michael Vronsky in The Deer Hunter, dug deep into LaMotta’s damaged mind, evoking the combination of paranoia, self-pity, and wrath that powered his short ascent and lengthy fall. He also notably altered his physique twice, first becoming a powerful young fighter and then gained 60 pounds to portray the boxer in older years. Actors as different as Christian Bale in The Machinist and Tom Hardy in Capone have tried similar radical physical transformations subsequently.

The film follows middleweight champion Jake La Motta, a legendary antihero. This was a bold and considerably darker take on boxing tome after the popularity of Rocky. Scorsese claimed that he had never really understood sports, and the film was filmed in black and white, which was unusual at the time.

Critics believed they were witnessing something exceptional when Raging Bull opened in New York cinemas on November 14, 1980, followed by a nationwide release on December 19. Film reviewer Vincent Canby said in The New York Times that LaMotta was a “titanic character,” and that De Niro provided “what may be the performance of his career.” De Niro earned his first and only Best Actor Oscar for the picture. (He previously won an Oscar for Best Supporting Actor in 1975 for The Godfather Part II; he hasn’t been nominated for a Best Actor Oscar since 1992’s Cape Fear.)

Scorsese used to cast unknowns like Joe Pesci, a small, stalky firebrand, and Frank Vincent, who went on to become a Scorsese regular. Pesci and Vincent met Cathy Moriarty at a Bronx bar one night and gave Scorsese her picture. Moriarty was cast in her debut acting role as the wife of Robert De Niro’s protagonist when she was 18 years old. She was a lookalike for the actual Vickie La Motta.

Cathy Moriarty claimed in an interview with the Guardian that she had never watched Raging Bull. “I mean, I’ve seen parts of it,” she says. “Just not in its entirety. Not in one sitting.” This is unbelievable: Moriarty’s portrayal of Vikki LaMotta, the savage boxer Jake’s wife, is indelible. Of course, it’s a gruesome picture, but that’s not why she avoided watching.

“It was the first time I’d heard my voice recorded,” she explains. “The film played and I said, ‘Who is that?’ They said, ‘It’s you.’ And I said, ‘That is not what I sound like. That sounds like a truck driver.’” The voice remains a wonder: a rasping aide-memoire of old New York. “I like it now,” she says. “It just took me a while.”

Cathy Moriarty had a front-row seat to De Niro’s performance while playing Vickie LaMotta, Jake’s second wife in the movie, and recalls being both startled and little terrified of her co-star. “On set, he was always in character,” says the actress to Yahoo Entertainment. “He’s probably the most disciplined person I’ve ever met. When we’d drive home from set, he would get out halfway and run behind the car because he was always training!” It took her four decades and two more films (Cop Land in 1997 and Analyze That in 2002) to come to know De Niro as De Niro. “I’ve seen him as a father, and I’ve seen him as a friend,” says Moriarty, who received a Best Supporting Actress nod for Raging Bull. “We still talk to this day. So I know the Bobby side, and I know the Jake side.”

She was working as a receptionist in Manhattan’s garment district and waitressing at a burger bar at the time. After three months of daily read-throughs with Scorsese and Robert de Niro at 5.30 p.m., she was cast. Though Scorsese had passed her by, she had a faint idea who De Niro was. Her preferences were more akin to those of Hollywood’s golden period. “I did not have a clue. But I also had no fear: I was 17 and I was better than you.”

Filming lasted almost a year. “Bobby taught me to listen and that was important, because if there was a script on Raging Bull, no one used it. He was good to me. Joe and Marty, too. I knew people would look at these older men and this teenage girl like, ‘Oh, I get it.’ But they were gentlemen. They also yelled at me when I needed yelling at.” Did she yell back? “Of course.”

When asked what her experience was filming the movie at a very young age, she said, “I first met with a lovely woman named Cis Corman, who was the casting director. She brought me into a room to meet Bobby and Marty. I was only seventeen and I didn’t have much fear, which was probably a good thing. They asked me to read some sides and I guess that since I wasn’t nervous, I did really well. If I had to do it today, I would have blown it!”

She was great – and was nominated for a best supporting actress Oscar. The first chapter of a fairytale was written; the rest went haywire. She didn’t have an agent and, just before the awards, went to Europe on holiday. “Smart, right?” She lost to Mary Steenburgen in the comedy Melvin and Howard. It was the start of a pattern: decisions that backfired, sheer bad luck.

She revealed to BlackBook that Scorsese didn’t give you her acting advice “he would just say, ‘What if it was this way?’ I admit that I was stuck there for a while, not knowing exactly what to do. For example, I thought my screen test was going to be shot with a video camera. What did I know? I didn’t know there was going to be a whole entire crew present. Right before we shot the first scene during the screen test, I was waiting for the crew to leave. Marty told me that they weren’t leaving. I said. ‘Okay, why didn’t you tell me that? Let’s go.’ Another actress was scheduled to come into screen test right after me and they wound up canceling her.”

De Niro’s metamorphosis for Raging Bull included channeling LaMotta’s hair-trigger fury. Despite having a screenplay, Moriarty and Scorsese — whom she regards as “brothers,” according to Moriarty — chose to improvise their way through situations. “Later on, I learned that you’d go to work and they’d give you sides and you’d read whatever was on the page,” she laughs to Yahoo Entertainment. “I don’t remember getting any sides during Raging Bull! They were like, ‘This what the scene is about,’ and I’d go, ‘OK.’”

She traveled to Los Angeles, determined to seize the day, but Hollywood producers questioned her accent. In an interview with The Guardian, she claims, “I didn’t even have an accent! You people have accents! People assumed I’d lived the life of Vikki LaMotta. I thought, ‘You know nothing about me.’”