Vince Vaughn defined the wise-cracking womaniser with his breakout role in Swingers almost ten years ago and in 2003 with Old School. Now he takes it to new comic heights in Wedding Crashers alongside fellow funnyman Owen Wilson. In between seducing the ladies, Vaughn has had huge success as the underdog in Dodgeball and the drug lord in Starsky & Hutch (which also starred Wilson).

You had body doubles perform the dinner scene where Isla Fisher gets her hands down your pants under the table. What a cop out!

We originally didn't have body doubles for the dinner table scene. David [Dobkin, director] had a... thing that we put in that didn't quite work out. Then he went away on his own and shot something else because that wasn't useable for the scene. Isla had a body double for the bed scene, but I didn't.

So how did that work out for you?

Yeah, it was fine. You're just tied up and got nowhere to go so... I was living the dream. Nobody told me I was going to be filming in heaven that day!

But it's your chemistry with Owen Wilson that is really the key to this movie, isn't it?

To me Owen Wilson is just a big dollar sign. I said, "Owen, here's how it's going to work, amigo: I'm gonna say something stupid, you're gonna roll your eyes, and the guy in the glasses is gonna yell cut. I don't wanna be late for the god****** Laker game!"

Could you at least make time for some adlibbing?

It depends on who you ask, but the facts of the matter are very simple. We [Wilson and Vaughn] actually went through and rewrote a lot of our scenes, and we rewrote a lot of the scenes for me and Isla as well - like the whole imaginary friends thing was something that we came up with. So we went through and changed a lot of the lines so that when we actually came to perform it, there wasn't as much improvising at the time, but it was stuff that we came up with that we thought would serve the scene better. Then from scene to scene, we would change lines to keep things fresh, but most of it was stuff that we came up with prior to shooting.

What kind of changes did you make?

In the first script Rachel and Bradley's character [Bradley Cooper] get married in the end and Owen's character is just an obstacle and that was it. I had the idea of saying, well, what would happen if these two people ended up in a different circumstance and that becomes the plot twist. I think obviously that made my relationship with Isla's character mean a lot more to the movie and it was just a smarter way of handling the turn of events versus the traditional, ‘Here's the crazy person!' with no sort of arc to it.

Did you also come up with those cheesy pickup lines?

Someone stole the stars and put them all in your eyes. Your legs must be exhausted from running through my dreams all night...

Ever had a date as scary as Isla Fisher in this movie?

Nothing comparable to that, no! But it was a lot of fun for me because Isla is very funny and also a good actress, so it was nice to go and do a scene and by default to be the one who's reacting to stuff. That kind of gave the movie a flow. The movie is an interesting animal in that it is a traditional buddy comedy between Owen and myself, but then he has a love story with Rachel [McAdams] and Isla and myself have one. So it's fun that you have a bunch of different stories that are all working in different ways.

Do you think your love life has suffered since introducing your lady-killer alter-ego in Swingers?

I find dating girls is easier once you've opened a movie. I would recommend it to anyone for picking up dates. If you've been on the covers of some magazines and been in a few movies that have been seen by people, for some reason, women seem to be drawn to you. Contrary to what you say, I think it's been helpful.

You seemed to really relish the dancing in those wedding scenes?

Was it Winston Churchill who said, "Never trust a man who dances"? That line always served me well - whoever said it - when I didn't want to dance, but I think it's fun to dance. I love that kind of dancing. You know growing up in Los Feliz there was all this swing stuff, which was fun too, but we took classes for the movie. What makes it look so effortless is the hard work that we put into it prior to shooting it.

Could there be a musical in the works for you?

Thank you for asking. There is a musical that Owen and I are actually working on right now. We play two rodeo clowns who leave the rodeo and become lifeguards at a park district pool outside of Chicago where we befriend a young Filipino boy who has an outie belly button and we teach him what it's like to get along with the other kids that summer. It's called Mr Sunshine and Owen plays Mr Sunshine.

How do you feel about the Frat Pack label that's been slapped on you, the Wilson brothers, Will Ferrell, Ben Stiller and Jack Black?

I've always found it odd. I've never even done a scene with Jack Black. I think that if there's truly any kind of common denominator it's Ben Stiller, who has hired people for different stuff and looked to do stuff with different people. He's initially the reason why everybody has sort of overlapped. Even with Owen, this is the first time we've ever really had an opportunity to do stuff together. I did a non-speaking cameo in Zoolander but we were never on screen together and then in Starsky & Hutch we had a little bit to do. Just a taste - just a pink spoon not the whole sundae - and then this one here was the first chance we had to really do stuff together.

But because there's chemistry between all of you off screen, aren't you more disposed to doing cameos in each other movies?

Yeah, I guess. It just depends on the people that you've worked with. I obviously had done something for Will [in Anchorman] and then he returned the favour on this and I find him funny. I don't think there's anyone more funny than Will is and I like Ben's stuff a lot, so yeah, definitely I'm fans of them but there's not a real consciousness of saying, "Okay, we're a group of people who are planning on doing stuff together". I think people prefer not being asked because a friend in need is a pest - you'd rather not have to go and do a cameo.

What can you tell us about the project you've got going with [writer/director] David O Russell? It sounds a bit more commercial than we're used to seeing from him...

Yeah, David O Russell has a movie that's interesting that's still being written. So I've talked to him about it and it seems like an interesting idea but there's nothing set for sure in the screenplay. I don't know if it is a more commercial project. I guess it kind of is, but it's still David O Russell. I don't think it's going to be something that's not with his signature on it. I hope obviously that people go to see and like it, but I don't know how commercial it will be, or not be, yet.

Did he initially write it with you in mind?

He wrote it... It was an idea he had prior to me and then I think he's sort of personalising it as I've talked to him about what I want to do. So, it's becoming more specific, yeah. I play a 60s gym teacher in Bangor, Maine and I work with a bunch of different schoolgirls who are tired of laughing at what the boys say and want to make some jokes of their own.

Have you ever been at a loss for words?

Plenty of times, sure. But then, like a doll you pull a string and you always have four or five things you could say, like helping the Filipino kid.

Wedding Crashers is released in UK cinemas on Friday 15th July 2005.