No more Mr Nice Guy

Even for an actor who has managed to strike a reasonable balance between Jurassic Park-type blockbusters and smaller, artier films, Sam Neill's character in Little Fish is quite something.

'Brad is very different material from the stuff I usually get,' he remarks. 'The role is really off the wall. I mean, an ageing, gay drug-dealing gangster isn't one you'd see on the CV all that often...'

But surely, at 59, with more than 20 years of solid filmmaking behind him - most recently as Kirsten Dunst's ultra-competitive father in Wimbledon and the cuckolded husband in Sally Potter's oddball romance Yes, spoken entirely in rhyme - nothing can phase him?

'These things make you anxious,' he says. 'You worry about whether you're suitable for the part. But you have to take the punt, don't you?'

Brad is certainly one to take risks. He's the linchpin of Rowan Woods's oddly tender thriller Little Fish: a married, closeted homosexual who, for years, has been having an affair with Lionel (Hugo Weaving), a former Aussie rules football star - and supplying his heroin habit as a twisted love offering.

The upshot of Lionel's addiction was that he turned young Tracy (Cate Blanchett) on to drugs. As the film opens, Tracy is clean and struggling to rebuild her life. In an odd parallel, Brad, too, is trying to tidy things up: getting divorced, closing his business and finishing his relationship with Lionel - a double blow to the crumbling ex-athlete's heart and thirsty veins. 'Before it all goes terribly wrong, Brad is working towards some sort of resolution,' Neill points out.

The film's drama stems from a bad deal but, unusually for a drugs flick, Little Fish is very warm-blooded. This has a lot to do with the actors' calibre and with Neill and Weaving taking such unexpected parts.

'It's a very ambitious piece of writing,' explains Neill's co-star Weaving. 'Lionel is so far removed from where my life is but I was instantly excited by the prospect of playing him because he exists in a number of different worlds.

'The football player was the base. Then I needed to have some understanding of what heroin does to someone over a period of 20 years. His sexuality was not really important to me but, in terms of the film, it is because one of his many relationships is with Sam Neill's character.'

Neill, too, feels great sympathy for the person he plays. 'There's something desperately lonely about him,' he muses. 'He has certainly lived in a very duplicitous way for a long time.'