Downton Abbey star Michelle Dockery has used a red-carpet farewell to the show to reveal she is pregnant with her first child.

The actress, 43, plays Lady Mary Crawley in the TV show and its movie spin-offs.

She debuted her bump as she walked the red carpet for the world premiere of Downton Abbey: The Grand Finale in London on Wednesday night.

Dockery walked hand-in-hand with her movie producer husband, Jasper Waller-Bridge, as they announced the news at London’s Odeon Luxe.

He is the brother of actress, writer and director Phoebe Waller-Bridge. He and Dockery began dating in 2019, became engaged in January 2022 and married in 2023.

It followed Dockery’s earlier engagement to public relations executive John Dineen. He died, aged 34, in 2015 following a battle with a rare form of cancer.

In 2017, Dockery told The Guardian that she considered herself a widow.

“We were engaged, and married at heart, and so I do consider myself a widow. … That’s the first time I’ve said that, and it’s a bit of a relief to say so,” she said.

Downton Abbey: The Grand Finale is the third and final film in the franchise, 15 years after the period drama first aired as a TV series and gained a huge following in Britain and the US.

Dockery reprises her role as Lady Mary, whose family journeyed to the south of France to uncover the mystery of the Dowager Countess’s newly inherited villa in the second film.

The latest film also brings the return of other cast members including Hugh Bonneville, Elizabeth McGovern, Laura Carmichael and Jim Carter.

Mary finds herself facing a public scandal, all while the family tackles new financial woes.

“[Creator and writer] Julian[Fellowes] has constructed a beautiful, if you like, love letter to the loyal audiences that we’ve garnered over the years,” Bonneville told Reuters on Wednesday.

“I think those who follow the show will find it a very moving and I think appropriate way to wind up all of the stories.”

Carmichael, who plays Mary’s sister Edith, said it had been “emotional to say goodbye”.

“We have done it a number of times … we always thought the TV show that was it, then we did one movie, and we’re like we should be so lucky,” she said.

“It’s nice to know this is it because we wanted to give it … the proper send-off.”

The award-winning Downton Abbey first aired as a series in 2010, originally set in 1912. It went on for six seasons and was followed by two earlier films released in 2019 and 2022.

“We wanted to prove that the people who’d prophesied that period drama was finished, we wanted to prove them wrong. But I don’t think it was more than that,” Fellowes said of when the show first started.

“At the beginning we thought we might get maybe two or three series out of it, but we didn’t think we’d become a kind of world phenomenon.”

Douglas Reith, who plays the Baron Merton, told the PA news agency that the films honour the legacy of the series.

“I think this one particularly, just going full circle and bringing it to a wonderful close, is right,” he said.

Asked if it was truly the end of Downton Abbey, Reith said: “I have not the foggiest clue, but I would think it probably is because we’ve gone down to the 1930s now.

“I think the old ones like me, I mean, we’d all be dead. Probably should be now already.”

Producer Liz Trubridge added: “I’ve learned never to say never, but I do think this is the final one in this incarnation.”

Downton Abbey: The Grand Finale will be released worldwide on September 12

-with AAP