Hugh Bonneville has said the cast of the Downton Abbey film is obsessed with the word game Bananagrams, adding that Dame Maggie Smith and Laura Carmichael are the reigning champions.

The popular game, which does not feature a board, sees competitors race to create words using as many of their lettered tiles as possible.

Bonneville, who reprises his role as the Earl of Grantham for the big-screen outing of the ITV drama, said it has become a crucial component of filming days on location as Highclere Castle.

He told the PA news agency: “It became quite popular amongst the cast, certainly at Highclere, when we were filming at Highclere in between scenes.

“Laura Carmichael (who plays Lady Edith) is annoyingly good at it – it’s sort of a bit like Scrabble but simpler, and she happens to have a brain that works brilliantly, and Maggie Smith (the Dowager Countess of Grantham) is very good at it as well.

“It’s very hard work, acting.”

Downton Abbey World Premiere – London
Laura Carmichael is a champion at Bananagrams (Ian West/PA)

Jim Carter, who returns as butler Carson, said: “It’s a game you can go and do a take and pick up very easily afterwards.

“We played it with George Clooney, didn’t we? He joined in. We did a charity appeal with George Clooney and he played.”

Asked if he played the game with his wife, Imelda Staunton, who joins the cast of the film as Lady Maud Bagshaw, he said: “Imelda and I do play Bananagrams at home actually, there is a little insight.”

David Haig, who is also a newcomer to the cast, said: “Over the years I’ve met a lot of the cast and know some of them quite well so it was like coming home in a way, and it was straight upstairs in Highclere to play Bananagrams with the upstairs mob.”

Downton Abbey is released in UK cinemas on September 13.