Gary Oldman talks sobriety and 'Harry Potter' at Cannes

British actor Gary Oldman, who plays a washed-up alcoholic writer in new Cannes film "Parthenope", said Wednesday he is celebrating 27 years sober.

The Oscar winner ("Darkest Hour") also addressed controversial remarks he had recently made about his role in the "Harry Potter" films, which upset some fans of the boy wizard.

Oldman made the remarks at a press conference at the Cannes Film Festival after the premiere of Paolo Sorrentino's "Parthenope".

The Italian coming-of-age drama, inspired by mythology, traces a beautiful young woman as she drifts through Naples and Capri.

Oldman appears briefly as famed novelist John Cheever, who in real life struggled with severe alcoholism -- a part that Oldman said was not much of a stretch.

"I just celebrated 27 years of sobriety," he said, to applause.

"My wife actually found a quote where (Cheever) says, 'My shaking hand reaches for the phone to ring Alcoholics Anonymous, and instead it remains at the whiskey, the gin, the vermouth,'" Oldman continued.

"I've been there. I know what that means. So coming to this role, there were things that I just instinctively understood.

"When Paolo said to me, 'I want you to play this sad, melancholic, drunken poet,' I went, 'Yeah, I kind of know what that is!'"

In the film, Cheever strikes up a bond with Parthenope, who adores the author's books but has grown disenchanted with her life.

- Actors always 'hyper-critical' -

Oldman was also asked about negative comments he recently made about his own performance as Sirius Black in film adaptations of J. K. Rowling's beloved Potter books.

Addressing why he had called the role "mediocre", Oldman clarified that he did not mean to "disparage anyone out there who are fans of Harry Potter and the films".

Instead, he regretted that he had not already learnt the character's tragic fate in later books when he first took on the role in 2004 movie "Harry Potter and the Prisoner of Azkaban".

"Had I known from the very beginning -- if I had read the five books and I had seen the arc of the character -- I may have approached it differently," he said.

"I may have looked at it differently and I may have painted in a different colour."

Besides, Oldman said, actors are "always hyper-critical" of their own work.

"If I watched a performance of myself and thought 'My god, I'm fantastic in this,' that would be a sad day. Because my best work is next year."

Reviews of "Parthenope" ranged from "exquisite" to "utterly vacuous", though most critics praised Oldman's fleeting appearance.