Black Swan star Natalie Portman has admitted she always feels anxious about tripping up during red carpet events.

The 32-year-old Oscar-winning actress explained that she worries about landing flat on her face at high-profile events.

Speaking to France's Madame Figaro magazine, Portman said:  ''It's a very serious game. I remember my first red carpets, I felt like I was wearing a costume, it was hilarious. Nowadays, I'm used to it: you just need to look happy even if you're wearing uncomfortable shoes or a dress you regret having chosen.

''My top tip? Looking confident and calm. My biggest fear? Tripping up. When I was pregnant, it was an obsession, I kept repeating to myself, 'Don't fall, don't fall.' ''

Portman, who recently became the new face of Rouge Dior lipstick, further stated that advertising a red lipstick was an obvious choice for her.

She said: ''Passion, of course. Confidence, strength, seduction, femininity. It's the colour of brunettes. When I put red lipstick on, it's because I want to be admired... by my husband.''