Actress of the moment Penelope Cruz in Blow

When Whitehouse saw Depp at the Warner Village cinema in Leicester Square, he shouted: "He's wearing the same bleeding clothes as when he appeared on The Fast Show - the dirty old tramp!"

Depp joked: "Yes I am," before Whitehouse added: "I'd cut his hair, wash him and then present him to the ladies."

The audience for Tuesday's screening included Jemima Khan, Tara Palmer-Tomkinson, Lady Victoria Hervey and singer Natalie Imbruglia.

Blow is the controversial true story of George Jung - played by Depp - who became instrumental in establishing the US market for cocaine in the 1970s.

Jemima Khan attended the screening

Jung claimed he controlled about 85% of the market during the decade.

Depp said meeting Jung "was kind of a trial by fire".

"I was thinking I hope I like him, and I hope he likes me," he added.

"But he was amazingly generous and he was absolutely himself."

Mixed reviews

The film also stars actress of the moment Penelope Cruz - who is also in Captain Corelli's Mandolin, and Ray Liotta.

The $30m (�19m) movie has taken more than $45m (�31m) since it opened in April in the US where it was given mixed reviews.

The film was compared unfavourably with the Oscar-winning movie Traffic, which also focuses on the US drug trade.

Tara Palmer-Tomkinson was also in the audience

Depp's performance in the film was particularly praised.

Director Ted Demme - nephew of Silence of the Lambs director Jonathan Demme - said: "You get probably one chance in a lifetime to work with an actor as talented as Johnny.

"He's a film-maker, not just an actor."

Demme added that Depp was particularly popular with the woman working on set when it came to shooting love scenes.

"When I said 'Cut' I could hear a collective sigh - and it was the eight women stood behind me," he said.

The film is a trawl through the 70s and 80s and the huge growth in cocaine use in the US at the time and Jung's role as a dealer to the rich and successful.

Depp has a child with singer Vanessa Paradis.

Often portrayed as the bad boy of Hollywood, he was arrested after a fracas with photographers outside of a restaurant in London in 1999.

The film is released in the UK on Friday.