When Stylist was invited to speak to Amber Heard about her latest film The Rum Diary, we weren't sure what to expect. Hollywood's latest amour du jour has laboured under a variety of labels as her movie profile continues to blossom.

But what is most striking about Amber when we meet in London is not her celebrated 'blonde bombshell' allure, nor her movie star status. Instead, the actress radiates a sense of old-school glamour and integrity that belies the fact she is just 25 years old.

It's the very quality that made director Bruce Robinson hire her on the spot for the role of Chenault in The Rum Diary, the 2011 adaptation of Hunter S. Thompson's classic novel.

"From the moment I clapped eyes on her, I knew she was the girl,” says Bruce. “I wanted someone who could stand out on the screen the way Catherine Deneuve did 30 years ago. And Amber is just that.”

Amber admits that playing Johnny Depp's love interest in the 1960s, Puerto Rico-based film was "a dream" and "an amazing opportunity."

But she is more reluctant to celebrate her image as a Hollywood sex symbol. "It’s very frustrating because I know that there’s much more to me and there’s much more interesting things about me," she explains. "I think I will not be the first to express some kind of frustration with the limited amount of parts that are offered to young women especially those who are seen as leading ladies. (The roles) are just not out there."

See more about what Amber has to say about working with Johnny, filming The Rum Diary and the difficulties facing women in Hollywood, below...

What attracted you to The Rum Diary in the first place?

Well, what didn’t, I guess is the question... I play opposite Johnny Depp in a beautiful love story written by one of my favourite authors, Hunter S. Thompson, directed by one of the most genius filmmakers Bruce Robinson and shot in Puerto Rico – I couldn’t have asked for a better combination. It’s such an amazing cast and such a wonderful story that I truly had no choice.

You read the book several times beforehand: did that add pressure to the role or did it help you?

Whenever you read a book you do take with you a certain cautiousness and I think an extra burden because there is this old axiom that the movie’s never as good as the book… but in this case we weren’t setting out to do better or worse. It’s in many ways different [from the book] yet protects and maintains the integrity of the subject matter. I think that with true artists like Johnny Depp and Bruce Robinson I felt safe in knowing that the work would be protected, whether it was from the book or not. I knew I was in safe hands.

What was it like working with Johnny Depp?

It was my first time working with him and as you can imagine, it could be seen as an intimidating process but Johnny does everything to counteract that. He’s such a wonderful presence on and off set, he’s an incredible, incredible human, a wonderful artist and a great actor. He’s so easy to work with, he makes you feel right at home from day one. I was lucky.

Was the audition process tough?

I auditioned several times for this part and it was a gruelling process in my opinion, just because of nerves and a lot of energy that goes into any such process. But I think the best things in life and the most rewarding things in life are the ones that don’t come easy anyway, so this was no exception to the standard. I was elated when I got the part. It’s a dream role, it’s an amazing opportunity and it’s a fantastic part.

What does it mean to you being a high-profile woman in Hollywood and are there still battles to be won in the way women are represented?

I think the main struggle for women in Hollywood and women in my position is to fight for true representation in the media and accurate representation of our many diverse qualities in stories. When only one or two percent of filmmakers are female, you can’t help but have some kind of bias. We have all of our characters and all of our stories told through the perspective and opinions of men, and that’s fine, but until we make up a significant or more significant proportion of the filmmakers things won’t change. And I think I will not be the first to express some kind of frustration with the limited amount of parts that are offered to young women, especially those who are seen as leading ladies. It can be a frustrating process and I am not immune to that because, you know, they [the roles] are just not out there, they’re just not written for us.

You're now widely recognised and referred as a Hollywood sex symbol - which is great, in a way - but you must also find it frustrating?

It’s very frustrating because of course, I – just like anyone – do not see myself in such limited terms. While I know that people might see me in a certain way, I know that there’s much more to me and there’s much more interesting things about me. I think it’s important for us to - especially women – to remember that there is a default mechanism that’s just ingrained in us in Hollywood and we just tend to characterize women in one of two ways – the first being either sexy or beautiful and that affords you very limited opportunities and a very, very limited scope of qualities that you can take on in characters. It offers you quite a bright spark but never a flame - it’s a spark and it goes out soon and those are the only two things you can do. If you’re labelled as sexy beautiful, then that’s it. You’ll tend to find that that’s all that’s in your character description.

While as in the other category, you are offered the ability to take on many different qualities – whether it be funny or strong or mean or flawed or vulnerable or intelligent or independent , humorous, witty – you name it, you have much more opportunities but yet you never get that spark you just have perhaps the smallest flame. And there is something to be said about the fact that we just in general in Hollywood we can’t seem to cross any of those two categories together, it’s either you’re in one category or another. If you’re in the latter category you cannot be seen as sexy. And I don’t know why the two categories are mutually exclusive but I try at work, I do my best to allow a more diverse understanding of female characters. I hope that in the future there’s more power to change a system I see as flawed.