Terry Gilliam says the death of Heath Ledger sealed the fate of his new film The Imaginarium of Doctor Parnassus.
Speaking as the fantasy film premiered at the Cannes Film Festival, the director explained he felt a sense of duty to finish production on the movie due to the energy and enthusiasm of its late star Ledger.
The Australian actor, who won a posthumous Oscar for his portrayal of The Joker in The Dark Knight, died on January 22nd last year after an accidental overdose of prescription medication.
Ledger's completed scenes remain in the finished film with Johnny Depp, Jude Law and Colin Farrell playing his character in different dimensions in the fantastical effort.
"The closing credit says 'By Heath and Friends' because the film changed with his death," Gilliam said as the film debuted to a warm reception at Cannes.
"He forced me to make changes and we wouldn't have finished it if it wasn't for Heath."
The former Monty Python star added: "Heath was enjoying himself so much and he was ad-libbing a lot, which I don't normally allow... but Heath was just brilliant at it and he got everybody else going.
"Everybody was just energised by Heath. He was extraordinary. He was almost exhausting because he had so much energy."
Gilliam, who recently confirmed he will again attempt to make The Man Who Killed Don Quixote - after the initial shoot was beset by injuries and weather disruptions in 2000 - admitted he had considered abandoning The Imaginarium of Doctor Parnassus after Ledger's death.
"Fortunately, I was surrounded by really good people who insisted that... we had to go out and find a way of finishing the film for Heath," he told the Associated Press new agency.