Actress Scarlett Johansson dresses up for premiere

Actress Scarlett Johansson looked just the part when she stepped out on to the red carpet for the premiere of her latest film The Black Dahlia last night.

The 21-year-old had matched her floor length gown and striking make-up with the movie’s 1940s setting.

She explained she’d spent several days hunting for the perfect outfit and said: ‘Hidden away I found a Forties embroidered silk dress that is a perfect fit, not just for me but for the era my film is set in.’

The movie, which opened the Venice Film Festival, is based on one of Hollywood’s most notorious murders – the killing of actress Elizabeth Short. Scarlett plays the girlfriend of one of the detectives investigating the murder.

In the film, she enjoys a sizzling romp with co-star Josh Hartnett and critics have complained they found it difficult to concentrate following the raunchy scene. The blonde star said: ‘Of course it’s nice to be considered sexy, as a young woman in my prime. But I try not to think about the sexiness. And I never think about it being distracting from a scene.’