On screen, he's known for playing the Incredible Hulk in films including Avengers: Endgame and Thor: Ragnarok, but Hollywood star Mark Ruffalo's latest role sees him breaking down barriers of a different kind.
The actor (52) plays corporate environmental defence lawyer Robert Bilott, who in real life made headlines when he took on an American chemical giant.
Bilott waged war against DuPont, which was accused of allegedly contaminating a water supply which affected the livestock and residents of a community in West Virginia.
For Ruffalo, it was a story that sparked his interest after reading an article about it in a well-known American publication.
He explains: "I read it and thought, 'This is incredible', the fact that I'm reading about this in the New York Times Magazine and not on the cover of every single major publication in the world is outrageous. This story is very cinematic and should be told in film."
There was another important element for Ruffalo, the sense of responsibility he felt in using his platform as a filmmaker and actor.
"We can entertain people but I also think if it's done well and it's done right, you can reach people with really important social, political, cultural messages - warnings," he says.
"Anecdotal storytelling that can have a profound impact on decision-making, legislation, attitudes. It's really important."
For the real-life Bilott (54), despite having been victorious in his initial battle, there was still a sense of urgency attached to getting the story told.
He says: "We're talking about chemicals now that are all over the entire world - this is not just West Virginia, it's not just the United States, these chemicals are in drinking water everywhere.
"And they're being found in human blood everywhere, including in the UK and throughout Europe. So it's something that we're really hoping through the film, that people are finally going to be becoming aware of massive worldwide contamination that's been going on for decades. That unfortunately most of us are just now learning about."
The film's director, Todd Haynes, reflects on Ruffalo's transformation into Bilott's character.
"I think at this point in Mark's career, he wants to bring his prestige, his impact as an actor, his talent, his passion to projects that have meaning to him and his life and his beliefs," he says.
"But there was a pivoting point where he moved from being a producer to really being an actor on this movie and really committing himself to getting inside - and in my mind, utterly transforming into somebody we've never really seen him play before, as Rob Bilott."
As well as the acting impact, Haynes - known for films such as Carol, Far From Heaven and 2007's Bob Dylan biopic I'm Not There - hopes the film will resonate in other ways too.
The American director says: "Well, of course, the relevance of the story, the fact that we are in an incredibly consequential election year right now, and that it came out in the autumn before our election, was driving the entire film into existence. I think we all felt there was tremendous purpose.
"But you need to really feel for the people and the story at hand, and you need to really put yourself in the shoes of Rob a lot and remember the people that he's fighting for.
"That was the challenge from a dramatic standpoint - all of these issues are so important, but it's the power of a narrative experience that puts you inside their experience."
In early February, Haynes, Ruffalo and Bilott attended an event in Brussels, where the film was screened in the European Parliament to key figures.
Bilott says it was "critically important" to get the film shown to decision-makers.
"The people that are being exposed for years have been the ones that have had to really get their own water cleaned up, trying to get themselves protected, and it really shouldn't be up to them," he says.
"The folks that are setting the laws and setting the regulations that are supposed to be protecting us hopefully now are finally beginning to understand the seriousness of this problem.
"And those are the people that we're hoping now will take action to help protect everyone that's being exposed - which is everyone."
Ruffalo is equally as passionate when talking about the event.
He says: "We did a panel at the EU Parliament after 700 people had seen the movie and it becomes really easy for people to have an earnest discussion when they have that kind of frame.
"The press has been great, states in the United States are moving forward on legislation; we met with a bunch of MPs in London that are also working on regulating on this.
"There's a willingness to do it, they need the help of the public's outrage to help and movies like this you can use to organise people and get policy makers to do the right thing.
"Outrage is very important and making people uncomfortable right now is very important."
Apart from Ruffalo, the all-star cast also boasts impressive names such as Anne Hathaway, Tim Robbins, Bill Pullman and The Good Place's William Jackson Harper.
Hathaway, who plays Bilott's wife Sarah, reveals her first knowledge of the story came with receiving the script.
"And my reaction unfolded slowly. At first, I was really fascinated by it, then angered, then I felt a huge range of emotions as I realised that it was ongoing," she says.
"I think in David and Goliath stories, we are expecting to see Goliath fallen at the end, and that's not exactly the case here. I kept waiting for that ecstatic release moment at the end and then I realised that this is not that story.
"This is harder. This story is more reflective of reality and something that involves all of us. So, at the end of it I felt more awake - I wanted to be a part of it. If it's going to be about all of us, I wanted to be there."
Dark Waters is out now. See review opposite