James Gunn Shares Why He Came Back for 'Guardians of the Galaxy Vol. 3' Before DC Move (Exclusive)

The director also recalls how he got the MCU's first F-bomb in the movie.

Guardians of the Galaxy Vol. 3 is an epic conclusion to James Gunn's space saga that's been nearly 10 years in the making. But it almost didn't happen at all.

"Totally, thousand percent, didn’t think I was coming back," Gunn told ET's Ash Crossan when they sat down to discuss the conclusion of the Guardians' MCU storyline.

Gunn was fired from the Marvel film by Disney in July 2018 after controversial jokes he made nearly a decade earlier were resurfaced on Twitter. Shortly after his firing, Gunn apologized, while the Guardians cast -- including Chris Pratt, Zoe Saldana, Bradley Cooper, Vin Diesel, Dave Bautista and more -- expressed their support for Gunn in an open letter, asking that he be reinstated as director. 

He was ultimately reinstated in March 2019, however, Gunn admitted that the damage had been done.

"Listen, I wasn't sure I was going to come back when it was offered to me," he shared. "I had to think about it."

"But the thing that made me come back was, of course, my cast, who have supported me so much throughout all of this," Gunn continued. "But really, the thing was, I just needed to finish Rocket's story. I knew that he had a story that I had in mind from the beginning. That was important to me. And I didn't want to leave the character hanging."

Rocket Raccoon, who is voiced by Cooper and played on set by Gunn's brother, Sean Gunn, is the central focus of GOTG Vol. 3, with flashbacks showing how he was cruelly experimented on as a baby rodent, and the tragic events that led him to become the bitter genius we all know and love.

"I've just seen so many movies where they're trying to save the universe and you don't really care, at the end of the day," Gunn said of crafting the final story in his Guardians trilogy. "You know, obviously we would care if somebody is really trying to save the universe. But after you've seen movie after movie after movie of saving the universe, every time, it becomes a lot more effective to see, you know, saving an individual... You're really concerned about just Rocket being saved."

That doesn't mean that the movie is an entirely solemn one. In true Guardians fashion, there are plenty of jokes and epic needle drops to keep fans engaged -- and even the MCU's first F-bomb!

"It wasn't in the script," Gunn admitted. "The way I direct actors is a little obnoxious. I have a microphone, there's speakers on set, and I'm just constantly yelling at the actors to do different things, and often throwing them lines of dialogue. People ask if there's improv on Guardians sets, there is -- literally 90 percent of it is me, offering new lines for people."

The moment in question comes as Peter Quill, aka Star-Lord (Pratt), is trying to tell Nebula (Karen Gillan) how to open the car door on an old station wagon. In the moment, Gunn recalled, he decided to add a frustrated f-bomb.

"I just said, 'Hey, say open the effing door!' And he did. It was funny," Gunn recalled. "Marvel and Disney had been fantastic with me. They kind of let me do whatever I want to do. They give me free reign. And I did not think that they were going to say OK to that particular thing, but it was nothing."

Despite the ups and downs he's had in the MCU, GOTG Vol. 3 will be Gunn's last foray into Marvel material onscreen -- at least for a while. The director and Peter Safran were announced as the co-chairpersons and CEOs of the newly rebranded DC Studios in October, and the pair has already started rolling out their plans to reinvigorate some of DC Comics' most beloved properties. However, Gunn said he's taking plenty with him from his experiences as he embarks on a new creative adventure. 

"Really the thing that drives me, that's important to being a filmmaker, is a sense of creativity and play," he shared. "You can start to get distracted by results, by adulation or money or these other things. And all of those are sort of the enemy to creativity and storytelling. You can have those things or not have those things. But the important part is focusing on the creativity and the storytelling and the characters, first and foremost."

Guardians of the Galaxy Vol. 3 is in theaters Friday, May 5.