Brendan Fraser has played plenty of big-screen heroes, ranging from “George of the Jungle” to Rick O’Connell in “The Mummy” movies, yet he believes his latest role — a severely obese man in “The Whale” — may be the most heroic character he’s ever played.

In the Darren Aronofsky-directed movie, which will be among the films featured at the upcoming Toronto Film Festival later this month, Fraser plays Charlie, a reclusive teacher whose health is rapidly declining as he reaches out to reconnect with his estranged daughter (Sadie Sink) before it’s too late.

READ MORE: Brendan Fraser Wanted To Be ‘Unrecognizable’ In ‘The Whale’: ‘I Gave It Everything I’ve Got’

“It gave me an appreciation for those whose bodies are similar. I learned that you need to be an incredibly strong person, physically, mentally, to inhabit that being,” he said during a press conference at the Venice International Film Festival, as reported by The Guardian.

“Charlie’s physical mobility is limited to his home space, which is his couch. His story is told behind closed doors. He’s a light in a dark space. I think it’s poetic that the trauma he carries is manifest in the physical weight of his body,” Fraser continued.

“I needed to learn to absolutely move in a new way. I developed muscles I did not know I had. I even felt a sense of vertigo at the end of the day when all the appliances were removed, as you’d feel stepping off a boat on to the dock here in Venice,” he added.

READ MORE: Brendan Fraser Wanted To Be ‘Unrecognizable’ In ‘The Whale’: ‘I Gave It Everything I’ve Got’

Out of all the characters he’s played onscreen, Fraser said that Charlie was the biggest challenge he’d ever faced as an actor.

“I looked different in those [‘George of the Jungle’] days. My journey to where I am now has been to explore as many characters as I can, and this presented the biggest challenge to me,” Fraser explained.

“By far I think that Charlie is the most heroic man I have ever played, because his superpower is to see the good in others, and bring that out in him,” Fraser said. “In that process he’s on his journey of salvation.”