James Corden and Ruth Jones haven’t handed in the ‘Gavin and Stacey’ Christmas special script yet.

James Corden and Ruth Jones are yet to hand in Gavin and Stacey Christmas special script

James Corden and Ruth Jones are yet to hand in Gavin and Stacey Christmas special script

Nearly everyone but the beloved BBC sitcom’s creators - whose characters Smithy and Nessa’s unanswered proposal of marriage left viewers shocked at the end of the 2019 Christmas special - are in the dark about the storyline for the programme’s finale.

The BBC’s Director of Comedy, Jon Petrie, admitted the script is kept within a “very, very tight circle” while chatting at the BBC’s comedy showcase.

He is quoted by the Daily Mail newspaper as saying: "I genuinely still haven't seen the script, James and Ruth won't let us look at it yet.

“Which I think is great, they are really keeping it under wraps and don't want people to see it outside of their very, very tight circle until they're 100 per cent certain of it.”

Jon admitted the top-secret element might be hard to maintain during filming.

He said: “I think it will be hard when they are filming it because it's such a huge show and everyone will want to watch, everyone in all the locations where it's shot, it will be obvious what's being shot.

“I suppose you have to take it as a compliment that it means so much to so many people.”

The pair agreed to make a finale episode of the show - which debuted in 2007 and ended in 2010, but came back for the festive edition nine years later - after James, 47, returned to the UK from the US after hosting ‘The Late, Late Show’ on CBS.

Most of the cast are said to have signed up to return, including the titular characters - who are played by Mathew Horne, 45, and Joanna Page - along with the fan favourites Rob Brydon, 59, Alison Steadman, 77, and Larry Lamb, 76.