Australian Heath Ledger broke through on to the international movie scene playing a sensitive hunk in 10 Things I Hate About You. Six years later, his performance as a gay cowboy in Ang Lee's Brokeback Mountain has turned him into a hot Oscar prospect. Ledger has also recently been seen as a ghost hunter in Terry Gilliam's The Brothers Grimm, and will soon hit our screens as the eponymous Venetian Lothario in Lasse Hallström's comedy, Casanova.

What appealed to you about Brokeback Mountain?

Firstly, I thought the script was beautiful. I feel like most of the scripts for movies or books I've read concerning love are recycled and a little stale, and I thought this was a very fresh and complex version of a story of love. Also, the character of Ennis really struck a chord with me. His battle with his genetic make up, what had been passed down to him from his father and his father's father, and their beliefs and their traditions, he was fighting against all that; he was a homophobic man who loved women and men, and I found his contradictions really interesting.

In order to survive his environment he has had to really assert his masculinity, hasn't he?

Yeah, he's the most macho character I have played. That was the point: love transcends all of that.

In America especially, a lot of straight actors seem afraid to play gay characters, fearful of the impact it could have on their image. Did you worry?

Well I don't have an image, and I didn't then. But it was a very difficult decision because it scared the hell out of me. And I didn't want to kiss Jake Gyllenhaal, you know? [Laughs] And then I just felt like that's probably why I should do it, because I feel like I further myself if I'm constantly testing myself.

How did you and Jake work out the more intimate moments? Did you just go for it? Presumably there was a lot of trust involved.

Yeah, but that wasn't an issue. We obviously trusted each other and we most definitely didn't just go for it [laughs]. It was highly choreographed and thought out. It had to be. I mean, what do you do? I wouldn't want to just go for it, if that's what you're saying. But my reservations towards actually going through with it, and my nerves, actually worked for the film, because Ennis was very reserved and nervous about doing it. So it was lucky.

It also presumably takes a lot of self confidence and knowing who you are to do a role like this.

That's not the statement I'm making but yeah, I'm definitely confident in who I am.

Do you take advice when considering something like this?

Advice on what?

Whether the subject matter is what you should be tackling, because this is risky material?

That's just a matter of opinion. I don't feel like I have anything to lose, so I don't really understand what I'm putting at risk. No, I didn't really take advice. Most of the people around me were really encouraging about it.

You recently shot a low-budget love story about two junkies, Candy, in Australia. How was that?

Performing in it was a lot of fun because it was the first time I had used my own accent in a film in eight years. I had forgotten how free a thing can be and how liberating it is to not be weighed down by an accent. It was f****** fantastic! You allow yourself to breathe in your accent, you allow yourself to mumble, and improvising is, like, at the tips of your fingers. So it was really enjoyable for that reason. But it was just gruelling subject matter and some of the most gruelling scenes ever.

Do you have any plans about the kinds of parts you'd like to play? How carefully do you think about it?

I don't have that much forward planning about what I want to do next, or in the future. I guess if I'm doing something like, say, Lords Of Dogtown, then I really like to flip the scale on the next job. That's how Brokeback and Casanova really complemented each other, because Brokeback was really intense and excruciating, and Casanova was all drinking wine and eating pasta. It was like a holiday. So I've got no future plans. As long as it scares me, as long as it's something new, as long as I get to scare other people... I don't know, as long as I get to evolve and grow as an actor and as a person, that's the stuff I'm after.

Brokeback Mountain is released in UK cinemas on Friday 6th January 2006.