Acclaimed actor Robert De Niro and renowned director Martin Scorsese have worked together for decades, beginning with the classic mob movie, "Mean Streets." Theirs is an artistic match made in heaven, but it almost never came to be. De Niro very nearly turned down his supporting role in "Mean Streets" back at the beginning of his career. Believe it or not, it was lead actor Harvey Keitel who convinced De Niro to stay on the project. Without Keitel, De Niro and Scorsese may never have worked together at all.

Keitel was actually in Scorsese's student film "Who's That Knocking at My Door." Outside of this first role, Keitel didn't have a lot of experience as an actor, but he was the first person that Scorsese cast when he landed his first commercial. "Perhaps I got the part of Charlie because Marty sensed that I came from a similar background," Keitel speculated, per Martin Scorsese: A Journey. "I don't think it was my expertise in acting that landed me that work, but the experience Marty saw in me."

De Niro also came from a similar background as Scorsese. In fact, they grew up in the same neighborhood and even knew each other as teenagers. "We knew each other … We had like a crossover of friends," the actor revealed. "When he did 'Who's That Knocking,' I said, 'He did this about the neighborhood, and he really understands it.'"

The young actor was impressed by Scorsese's student film and wanted to work with him on his first commercial feature, "Mean Streets." "He offered me four parts — not Charlie, that was Harvey's part, but four others," De Niro recalled. "I didn't know which one to do." He wasn't sure if he should do any of them at all — until he ran into Keitel.

De Niro Almost Turned Down The Part

When De Niro was offered a supporting role in Scorsese's 1973 film "Mean Streets," he wasn't sure if he should take it. One chance encounter with his future co-star made him reconsider, the actor told Interview in 2012:

"I remember when I was up for 'Mean Streets,' I ran into Harvey Keitel in the Village — we were friends — and he'd already been cast in the movie as Charlie. I had done a couple of leads in movies before so I said, 'Well, careerwise, I should be playing Charlie.' I didn't say it like a wiseass. I was saying it sincerely, but not in a way that was threatening to him. Then Harvey said, 'You knew who you should play? Johnny Boy.' And that clicked. I played Johnny."

The actor had previously starred Brian De Palma's film "Hi Mom!," but he admits it was cocky to turn up his nose at a supporting role in "Mean Streets." "As an actor who's starting out, you can't say, 'Hey, I'm too good for this,'" he explained. "You gotta do it, because people see you, your name gets around, and it has a cumulative effect."

It was through "Mean Streets" that De Niro and Scorsese's relationship evolved from acquaintances to coworkers to life-long friends. "[W]e became grown-up friends. Today, we are good friends and best friends when we work together," the actor shared with The Baltimore Sun.

Without Keitel guiding De Niro in the right direction, he may have missed out on starring roles in "Taxi Driver," "Goodfellas," and a handful of other incredible Scorsese films. More importantly, audiences would have been deprived of De Niro's incredible performances. Scorsese, Keitel, and De Niro launched their monumental careers together, and they couldn't have done it without each other.

Read this next: Every Martin Scorsese Feature Ranked From Worst To Best

The post Harvey Keitel Changed Robert De Niro's Mind About His Mean Streets Role appeared first on /Film.