Lily Cole at the opening of The Imaginarium Of Doctor ParnassusThe Imaginarium Of Doctor Parnassus, the last film Heath Ledger made before he passed away, has opened at the Cannes film festival.

Stars including Lily Cole, who appears in the movie, have been paying tribute to the actor.

Heath was midway through filming the adventure fantasy flick in January 2008, when he tragically died of an accidental overdose aged 28.

Heath's character was rewritten to physically transform throughout the film in light of his sudden death, with Johnny Depp, Colin Farrell and Jude Law stepping in to take up the role.

Lily, who stars as Valentina in the epic, has spoken out about Heath as the film takes centre stage at Cannes.

"Of course it was weird and difficult going back to work after Heath died," she told Marie Claire.

"We were mourning him and now we had to work opposite actors who were playing the same role. Heath Ledger

"It’s a testament to what great actors they are that they managed to make that work," she added.

"And also they were friends of his, so they were missing him too."

Terry Gilliam, the director of The Imaginarium Of Doctor Parnassus, also remembered Heath and his role in the cult flick.

"I think it was people's love for Heath that meant that this film was finally done," Terry said, in a press conference at Cannes.