Two years after collaborating on the Oscar-nominated film A History of Violence, director David Cronenberg and actor Viggo Mortensen are set to take the 2007 Toronto International Film Festival by storm with the world premiere of the Russian mob drama Eastern Promises.

At a press conference yesterday, TIFF organizers announced the $30-million-plus feature film, which also stars Naomi Watts, will be a gala presentation, along with Denys Arcand's L'Âge des ténèbres (Days of Darkness) which nabbed the closing-night slot at this year's Cannes Film Festival.

Yesterday, Cronenberg said he was thrilled to be part of the festival yet again, telling the crowd packed into the Imperial Room at Toronto's Fairmont Royal York Hotel that he doesn't feel like he's actually made the movie, "until it's been shown at the Toronto film festival."

Then the director introduced his leading man, adding that it was sheer luck Mortensen was in town to attend the press conference. "Viggo just happened to be in town doing a little dialogue replacement because we thought his Russian could be refined a little bit more," Cronenberg joked.

Cronenberg added that, while shooting in Britain last fall, the subject matter of the film - it's about the Russian mob in London - suddenly "became rather hot news. In fact, really hot, like radioactively hot."

Both Cronenberg and the actor lived a block away from exiled billionaire Boris Berezovsky's building, which was stormed by British police after they detected traces of radioactive polonium. Berezovsky was a close friend of the former Russian spy Alexander Litvinenko, an outspoken critic of the Kremlin who was poisoned with thallium and died last November.

Mortensen told the crowd he viewed his collaboration with Cronenberg on A History of Violence - nominated for two Oscars - as "a very long, and complicated, rehearsal for Eastern Promises.

"I felt very comfortable, right away, with David from the first time. This time, we found a shorthand that meant we could work very quickly and efficiently with each other. We knew the good, the bad, and the ugly about each other," the actor cracked.

Cronenberg added that he often found Mortensen comforting cast-mates who weren't used to the director's style. "I'd see them sobbing in corners, and Viggo saying, 'It's okay. It's okay. He's always like that.'"

Eastern Promises, which started shooting last November in London, follows ruthless gangster Nikolai (Mortensen) who is tied to one of London's most notorious organized-crime families. Written by Steve Knight (Dirty Pretty Things), Nikolai's existence is shaken when he crosses paths with Anna (Watts), an innocent midwife who unwittingly uncovers potential evidence against the family.

Mortensen added the film was difficult to shoot, not just because of the subject matter, but because London is so frenetic. "People who see the film will find it a pleasant - and in some cases, not so pleasant - experience."