Just hours before the world premiere of his Eastern Promises, David Cronenberg adopted the persona of a comedy night host, joking that red-hot Viggo Mortensen, leading man of his grim crime thriller, was not equipped for its bath house fight scene.

‘At first we thought it was going to be a problem with Viggo being naked, but when we explored that, to my surprise, we found that Viggo did not have any genitals. We had to CG [them] in to make it look realistic,’ he said at the press conference on Saturday afternoon.

The press howled with laughter, so Mortensen quietly chimed in: ‘That’s why they had to reduce my salary.’

The actor/director team, who worked together previously on A History of Violence, have developed a certain momentous, black-humor shorthand, and the panel of Eastern Promises actors — including Naomi Watts and Vincent Cassel — were like strings on Cronenberg’s personal violin, praising him for his masterful directing skills.

‘David, you don’t tell us much on the set,’ Cassel said to him before turning to the audience, ‘and the result of that is that you have a great sense of freedom on the set.

‘David sees and hears everything on the set,’ he added. ‘I was always amazed how I could make a joke on the other side of the set, and David would see it. You also know that if you do something that is too much, he will see it. If you are kind of asleep or lazy, he will see it.’

Cronenberg soaked it up, but was clearly not in the mood to be serious. Asked about Cassel’s or Mortensen’s acquired Russian accents, he grinned: ‘It was like some creeping disease. You wake up one morning and everyone you know speaks Russian, and you don’t.’ Again the press laughed out loud.

When asked what advice he might give to young Canadian directors, Cronenberg cracked: ‘It’s always been my goal to crush the young. Only because they want to supplant me and my private struggle.’

But, for a moment, he was earnest. ‘It’s really hard for me to give pragmatic advice to young directors because things were so different for me when I was starting out. Everything was different,’ he said.

‘But I’ve discovered there’s a lot of mythology around about what you must be to be a director. And it’s all mythology. I’ve actually had some kids come on the set, and they were really depressed because their professor told them they really don’t have the personality to be a director, because they’re not mean and nasty and brutal and cruel and like to humiliate people.’

Mortensen interrupted. ‘Tell them about your riding crop,’ he said, to which Cronenberg answered, ‘I don’t use it to ride a horse.’