The director of new film The Master has acknowledged that the founder of Scientology L Ron Hubbard was the inspiration for the titular character.

The movie is set in the 1950s and it stars Philip Seymour Hoffman as a charismatic cult leader who captivates Joaquin Phoenix's troubled Second World War veteran.

Paul Thomas Anderson says the fact that Hoffman's character, Lancaster Dodd, was inspired by Hubbard "is not an elephant in the room."

"There's a lot of similarities to the early days of Dianetics," Anderson told a news conference on Saturday ahead of the highly anticipated film's world premiere in competition at the Venice Film Festival.

"I don't really know a whole, hell of a lot about Scientology, particularly now, but I do know a lot about the beginning of that movement and it inspired me to use it as a backdrop for these characters."

Joaquin Phoenix, who is appearing in his first film in two years, displayed some mildly erratic behaviour during a press conference for the film, fidgeting, lighting up several cigarettes and going back stage at one point for two minutes.

The Venice Film Festival runs through until Saturday 8th September when the winner of the Golden Lion will be announced.