Charlize Theron is laughing about a memorable day she had on the set of her new comedy western A Million Ways To Die In The West.

It involved a particular scene with her co-star Liam Neeson, who plays her bullying outlaw husband Clinch Leatherwood. Theron was required to whack a trouser-less Neeson over the head and cheekily place a flower where the sun doesn't shine.

"I said what any healthy woman would say," recalls Theron, giggling. "'I get to see Liam Neeson's butt!' That's what happened. I can think of so many worse jobs!"

Born in South Africa, Theron has been steadily working for the last two decades, famously arriving in the States aged 19 with just 400 dollars to her name and a boat-load of ambition to make it in Hollywood.

Yet, despite the plaudits for her performances in heavy-hitting dramas, particularly as serial killer Aileen Wuornos in Monster, for which she won a Best Actress Oscar, Theron's isn't the first name that springs to mind when it comes to comedy.

Fully aware of this fact, she says she "begged" Ted creator Seth MacFarlane, who helms and also stars in A Million Ways To Die In The West, to give her the role of mysterious gunslinger Anne.

"I've been interested in comedy for a while, but it's been tricky because audiences know me so well doing something very different," admits the 38-year-old.

"In fact, what also interests me is odd comedy. Those are very rare. The combination of this script and Seth directing was a slam dunk for me. I started begging instantly. I closed the script and started begging."

Odd is a very good description of this film.

MacFarlane plays Albert, a sensitive sheep farmer who feels out of sorts with the hard times he lives in. When his girlfriend Louise, played by Amanda Seyfried, dumps him for the smug Foy (Neil Patrick Harris), he becomes friends with Anna - who advises him on how to win fickle Louise back, not realising Anna's connection with her husband Clinch. There's also a song about moustaches, urinating farm animals and plenty of toilet-humour gags.

While the jokes may not be everyone's cup of tea, it's clear that stepping away from serious drama was rather freeing for Theron.

"I loved watching this movie, because it felt like I was actually seeing myself," explains the actress, who has a two-year-old adopted son, Jackson, and revealed earlier this year that she's dating Sean Penn .

Going into the unknown could be daunting prospect for some, but Theron was quite clear in how she should approach the comedy script.

"The worst thing you could do is show up and think you're going to be funny, because the universe doesn't work that way," says the star, who studied ballet in Johannesburg as a youngster. "If the writing is good and you have good director like Seth, who is at the top of his game, the comedy will naturally come from that. You won't have to force it."

Likewise for Theron, who shaved her head for the upcoming Mad Max film and piled on the pounds for 2003's Monster, the chance to play a version of herself, instead of someone completely alien, was a nice change.

"I think there's an idea that actors have, where unless you're completely transforming and disappearing into a character, you're not really doing your job," says the former model, whose blonde locks have grown back to a short bob and are today coiffed into playful curls.

"There was something refreshing after 20 years of doing this; watching a movie, seeing and hearing myself and feeling like that was enough to tell that narrative - that there's nothing wrong with that."

Looking back on those 20 years in the business, Theron can see how much her 2004 Oscar win has helped to shape her career.

"I can't be jaded about it, winning an Oscar is definitely a highlight," she says. "Just because it's from your peers, and it's something that's really the cause of a lot of opportunity coming your way afterwards. That was definitely something I didn't expect in my career."

Theron, who was the first South African to win an Oscar - which she now keeps on a shelf in her library at home - is appreciative of how things have turned out for her.

Her early years weren't always easy as her father was an alcoholic. Aged 15, she witnessed her mother shoot him dead after he tried to attack her in a drunken rage.

"I'm completely aware of how blessed my career and my life has been," she says today. "I think my 22-year-old self would probably just be jumping up and down going, 'Woohoo, we're still doing it! We're not a waitress! We kept going!', so I'm very grateful for that. You have to be in this business."

Although she has recently criticised the media intrusion on her personal life that comes with fame, Theron seems keen to count her blessings today.

"This business is not something that a lot of people get to experience," she reasons. "So if you're fortunate enough to be in that position, you better be grateful about it."


:: The Devil's Advocate (1997) - A fresh-faced Theron found herself playing Keanu Reeves' wife in this intense thriller about a lawyer who gets more than he bargained for.

:: Monster (2003) - She won a Golden Globe and an Oscar for her portrayal of real-life prostitute and serial killer Aileen Wuornos.

:: The Life And Death Of Peter Sellers (2004) - In this biopic about the British actor, Theron plays Swedish actress Britt Ekland, who was Sellers' second wife.

:: North Country (2005) - This drama about a woman miner who successfully files a sexual harassment case won Theron nominations at the 2006 Oscars, Golden Globes and Baftas.

:: Arrested Development (2005) - As batty Brit Rita Leeds, Theron showed that she can turn her hand to more comic roles.

:: A Million Ways To Die In The West is in cinemas now