Having previously played DC Comics' The Joker, Oscar winner Jared Leto takes on Marvel's Morbius in the first big screen adaptation of the vampire-like character.
"It was an incredible opportunity," Leto told Reuters in an interview.
"There are so many of these iconic Marvel characters that have already been interpreted that it's very rare you get asked to step into the shoes nowadays of a character that's never been realized before."
Released in cinemas this week, "Morbius" tells the story of Michael Morbius, an altruistic and infirm biochemist who suffers from a rare blood disease. Trying a cure, he morphs into a brutal monster with a thirst for blood but learns to harness his powers.
"In the beginning... he's very sick and frail and fragile and really at the end of his life, and he's searching for a cure to this brutal disease. And then he gets strong and powerful and then ultimately monstrous," Leto said.
"The challenge for me was digging into these three unique... versions of the same character... there's this super challenging transformation and I enjoyed that. It was rewarding."
British actor Matt Smith, known for "Doctor Who" and "The Crown", plays Morbius' lifelong friend Lucien, renamed Milo by Morbius when they were children.
"They share the same very debilitating disease and became very close as a result of it over the years," Smith said.
"They're different in personality - one's English, one's American and their souls are quite different. But their ambition to find a cure is... the great kind of similarity and the great bond that keeps them together over the years."
Director Daniel Espinosa said it is Morbius' duality that has earned him a following in the comic book world.
Asked whether films about super- or anti-heroes like Morbius trying to heal the world felt relevant in the current climate surrounding the Ukraine crisis, Espinosa said: "To give people respite is not to give people a shot of diving away from the responsibility."
