Julia Stiles was told she was "too serious" as a young actress.

The 45-year-old movie star started acting at age 11, performing with New York's La MaMa Theatre Company, and she enjoyed huge success around the turn of the century - but one piece of advice always stuck with Julia.

Speaking during an Instagram video, Julia shared: "I remember being an auditioning actress as a teenager, and every single audition that I went to, they'd be like, 'You need to smile more. Just smile, be more bubbly and effervescent. Because you're so serious. You're too serious'.

"And that just made me angry, but luckily I found the role of Kat Stratford in 10 Things I Hate About You."

The 1999 romcom proved to be one of the biggest successes of Julia's career and she relished playing the role of Kat Stratford, having been preferred for the part over the likes of Eliza Dushku and Katie Holmes.

Julia said: "It was just so much fun playing her because she wasn't driven by everybody else's judgment of her. How awesome that, like 25 years later, different generations of ladies are still responding to her and that movie?"

The actress previously admitted that she struggled to cope with the pressures of fame and success during her teenage years.

She told the Evening Standard newspaper: "When 10 Things came out I was 17 and had to learn how to navigate the fame. I was like a baby giraffe stumbling to try and figure out how to walk. I had no concept of what it would mean to be photographed without being aware of it. I'm not that much of an exhibitionist."

Julia has also learned to live with the ebbs and flows of Hollywood.

She said: "Hollywood tends to develop crushes on actors and the excitement faded.

"The challenge is to be able to keep a career going after that, when you are not the bright, young shiny thing. I had times where nobody knew what to do with me and work wasn't coming. I've learned how to deal with how ephemeral the industry is by being grounded. I don't cling to success anymore and I am a little more comfortable in my own skin."