Sienna Miller played down her role in the film

Director Matthew Vaughn, who produced Lock, Stock and Two Smoking Barrels, arrived at the London launch with wife Claudia Schiffer.

"It's had better reviews than Lock, Stock and Snatch so I can't complain," said Vaughn.

Miller, who has a small part in the film, was not accompanied by boyfriend Jude Law at the event on Thursday.

Law was thought to have missed the premiere in Notting Hill because he was baby-sitting his children, who live with their mother Sadie Frost.

I was thrilled to be part of it but... I only have a very small part." Sienna Miller

Miller, 22, flew back to London from Venice, where she is filming, to promote the movie, which is based on the crime novel by JJ Connolly.

She played down her part in the film, saying: "I have never had a premiere before.

"I was thrilled to be part of it but I only worked a week for the film, I only have a very small part."

Crazy about acting

The star's stepmother, interior designer Kelly Hoppen, was also at the premiere.

She said: "She's the same old Sienna, nothing will change her. She's just very chilled and is crazy about acting."

Supermodel Schiffer, 34, who is pregnant with her second child, said she was delighted with her husband's new work.

"He's really confident, I'm very proud. I love the movie," she said.

Talking about her pregnancy, she said: "I feel very well, just a little tired now. I eat whatever I want and I'm not doing any exercise."