Downton Abbey's stars brought old-school glamour to London's Leicester Square tonight for the premiere of series five.

The hit ITV period drama held a special red carpet event hosted by the Cinema and Television Benevolent Fund, with star guests Jim Carter and Laura Carmichael arriving in style in a vintage car.

Carter, who plays butler Carson, said: "We were a bit nervous about getting out of it because it was a slightly inelegant backside first exit from the car and Laura was nervous about her short skirt.

"But it was nice to crawl around the streets in a Bugatti."

Carmichael, who plays Lady Edith, said her character's storyline involving a secret love child with missing lover Michael Gregson had made for a different experience this series.

She said: "I've loved this series. You're all wanting exciting things to happen to your characters and it's been wonderful to play."

The show's creator Julian Fellowes and producer Gareth Neame promised fans an end to Downton was not in sight yet.

Neame said: "I think the thing that limits it is the characters start to get older than the actors because we rattle through history, so we couldn't go up as far as World War II."

Fellowes added of working on the programme: "You always have to remember period drama is history light - you can enjoy it but you don't have to get up at four in the morning to clear out the grate."

George Clooney recently visited the set to record an appeal for ITV festive fundraising show Text Santander and Fellowes said: "I thought he was very generous to do it because he didn't have that long in England and he spent a whole day of it supporting the ITV group of charities, so that seems to indicate that his heart is in what they call the right place."

Asked whether Clooney would be welcome back for an acting role, he said: "As far as I'm concerned, he can have whatever he likes. He can take over from Maggie (Smith) if he likes."

The premiere also welcomed Lesley Nicol, who plays cook Mrs Patmore, but she said she had missed Clooney's day on set.

"It was spectacular, I was just completely gutted that I wasn't there. Never mind, we got Sue Johnston as a guest who is cracking and my friend and I'm very happy she's there," she said.

The Cinema and Television Benevolent Fund supports people working behind the scenes in film, cinema and television who are facing hardship.

Downton Abbey series five returns to ITV on Sunday.