The 'Melancholia' star checked into the Cirque Lodge Treatment Centre, in Utah, to be treated for the mental health condition in February 2008 and she claims the pressures of her career caused her problems.
Talk show host Ellen DeGeneres asked her: "There is no way to bring up with out saying what it … You suffered from depression."
To which Kirsten answered: "It's not something I feel like totally comfortable talking about but yeah, it's a very personal thing … I dealt with it. Yeah. That and it's also interesting as an actress you're supposed to be sensitive and vulnerable and have this side to you. But then your supposed to be super sociable and 'on' and like nice to everybody. That's a weird dichotomy. It's a lot to ask of a person. It's not a normal thing."
The 29-year-old actress believes it was the right thing for her to do to have treatment and take a break from Hollywood, because she was able to return to her career reinvigorated.
Kirsten – whose breakthrough role came when she was just 10 in 'Interview with the Vampire' - added: "I definitely took a little bit of a break. And also, when you're in your 20s you need figure things out and take a step back. I had been acting so long, all my life. I think I just needed a little bit of some perspective. It was good for me and it re-inspired what I do, too."
However, Kirsten avoids the Hollywood party circuit and only attends the premieres of her own movies. She said: "I avoid the red carpet as much as possible. You have to do it to promote your movies obviously but you won't see me at an event just for the sake of it."