Mark Ruffalo Reveals How Robert Downey Jr. Convinced Him to Play the Hulk in the First Avengers

It’s hard to imagine anyone else playing Bruce Banner after Mark Ruffalo took over the role — but it turns out that it took some Iron Man-level persuasion to convince Ruffalo, 52, to take the job.

The I Know This Much Is True star was hesitant to dive into the Marvel cinematic universe as the Hulk in 2012’s The Avengers, directed by Joss Whedon, he shared with Jimmy Fallon on Friday in a PEOPLE exclusive clip of The Tonight Show Starring Jimmy Fallon.

“I was scared,” Ruffalo told the late-night host of being approached for the role. “I didn’t know what I could add to what I already thought had been done so well before me.” The last actor to play the comic book character was Edward Norton in 2008’s The Incredible Hulk. 

Among the reasons for his hesitation, Ruffalo told Fallon, was that he had “only been doing indie movies up ’til that point.”

“So I was like, ‘I don’t know if I’m the right person for this.’ And Joss Whedon’s like, yeah, you are the right person,'” he remembered.

But the director wasn’t the only one to try to convince Ruaffalo he’d make a great Bruce Banner — his soon-to-be costar Robert Downey Jr. also rung him up to do some cajoling.

“And then I got a call from Downey, it must’ve made it to him that I was hemming and hawing, and he just simply said, ‘Ruffalo, let’s go. We got this.’ In true Iron Man fashion. And then after that, I was like, ‘I guess I have to do it.’ “

Marvel is notoriously secretive about its projects, but Ruffalo managed to get his hands on a few pages of the Avengers script before officially agreeing to star in the movie, and reading those pages is what ultimately confirmed his interest in playing the superhero.

“I wanted to read a script, and they don’t give you scripts. I made a promise when I was a young actor that I would never do another movie without reading a script beforehand, because it’s a recipe for disaster, and then you get stuck in something — our only power as young actors are our ability to say ‘no’ sometimes,” Ruffalo explained. “And so I was like, ‘I need to read something,’ and the studio was like, ‘We’re sorry, we don’t give anything out.’

But Whedon slipped Ruffalo 20 pages of what he had written so far of Bruce Banner’s character, and Ruffalo was hooked.

“I read that first scene of when Scarlett [Johansson], when Black Widow finds Banner in India, and I was like, ‘Okay, I love this.'”

“It was different, you know,” Ruffalo said of the script. “I was like, ‘Oh, okay … It’s humorous and it’s kind of playful and I think I could do something with it.’ “

As Marvel fans know, Ruffalo went on to star in several more Marvel movies, including last year’s blockbuster hit, Avengers: Endgame.

The actor recently revealed he’d like to star in a stand-alone Hulk film given the opportunity.

“We’ve never really followed him into his life. He’s always kind of off on the side,” Ruffalo mused in an April interview with Variety. “He’s like the Rosencrantz and Guildenstern of the Avengers. It’d be interesting to fill in all the blanks about what happened to him in between all these movies.”

“There’s nothing completely at a place where it’s a done deal,” Ruffalo said, adding that the idea has been floated of having his character appear in the upcoming Disney+ series She-Hulk. “If we come up with something good, that would be really interesting. Right now, that’s about it. That’s all there is on the table.”