Downton Abbey the movie: The Crawleys prepare for a royal visitor

But in the forthcoming film they get the royal seal of approval as King George V and Queen Mary come to stay. The first full trailer for the Downton Abbey film, which has been released online, sees the Crawleys and their servants preparing for their royal guests in 1927. With much anxiety about the impending visit, Lady Mary (played by Michelle Dockery) even calls on retired butler Carson (Jim Carter) for help.

Other cast members from the ITV original who feature include Hugh Bonneville and Elizabeth McGovern as Lord and Lady Grantham and Dame Maggie Smith as the caustic Dowager Countess – who provides a comedy moment as she struggles to rise from a curtsy.

Allen Leech, who plays estate manager Tom Branson, said: “We wanted to be sure we got the right script. Taking something from TV to film, we wanted to make sure it was bigger and bolder and more theatrical.

“We locked Julian [Downton creator Julian Fellowes] in a room for three years and came up with the script we have today.”

In a Twitter Q&A, Fellowes admitted feeling “daunted” at the prospect of taking Downton to the big screen.

He said: “I was excited but also quite daunted. You can take stories across different episodes and do all sorts of things. Whereas in a movie, every story has to be resolved and every character has to have a story.

“But to go on with the stories and characters of Downton, that was pleasant to me – I like them all.”

Downton Abbey will be in cinemas on September 13.