IN a career that has seen her playing a frumpy bespectacled brunette in Being John Malkovich, a blonde undercover detective in Charlie's Angels and voicing cartoon character Princess Fiona in Shrek, Cameron Diaz is probably remembered most vividly for her appearance in gross-out comedy There's Something About Mary.

Now the actress - who reaches the milestone age of 30 on August 30 - is building on her successful portrayal of Mary, the laid-back, sweet-natured beauty who all the men wanted to be with, in another no-holds-barred comedy, The Sweetest Thing.

But this time, Diaz says, the film is one for the girls. ''The thing about this movie is it has a heart. It's really a girl's gross-out comedy. It's soft around the edges."

She plays Christina, a girl who's having fun on the singles scene and, along with her two friends - played by Christina Applegate and Selma Blair - is looking for Mr Right Now rather than Mr Right. That all changes when a brief encounter sends her off on a road trip to find her man.

Unlike the string of Hollywood

bad-taste comedies filmed from the male point of view which followed the success of There's Something About Mary, this time the trio of women are the aggressors and the men are the objects of desire.

''The girls start going to clubs because they don't want a serious relationship. They're into a reel-them-in-throw-them-back mode,'' says the actress.

''It might be offensive to some people, but you know what, if they don't like it they don't have to watch it,'' she maintains. ''It's just silly fun. We kept it at the level of screwball nonsense where people have a good time.''

And while the film's humour may not appeal to everyone, Diaz enjoyed getting to have fun on screen, especially after her role in Martin Scorsese's long-delayed drama Gangs of New York, in which she stars alongside Leonardo DiCaprio and Daniel Day Lewis.

The arduous shooting schedule of this epic about ethnic gangs in 19th century New York was one of the motivating factors behind doing The Sweetest Thing, she says.

''After doing a couple of films that were more serious and dramatic I just thought I wanted to have some fun on a film and be myself."

Being herself means being gregarious and friendly, something Diaz says she now has to watch in public because of her fame.

''I'm naturally the kind of person who smiles at other people when I walk in the mall and I can't do that now because it becomes an invitation to come and talk to me,'' she admits. ''I have to walk with my head down, but there's still part of me wants to make eye contact and smile.''

At the movie's core, Diaz believes there's more than simply gross-out jokes - it's also about the importance of same-sex friendships. But it wasn't hard to portray the close friendship between the trio of friends as the three actresses found they clicked together while filming the movie.