James Corden gave a major Gavin & Stacey update as he appeared on Capital Breakfast radio on Wednesday morning.

The iconic BBC comedy is set to return on Christmas Day for its last ever episode, with fans hoping to see the outcome of the dramatic proposal cliffhanger between Nessa (Ruth Jones) and Smithy.

And Smithy actor James, 45, has now told host Jordan North that the final script will definitely be ready this Friday meaning shooting can start very soon.

Jordan asked him in an interview: 'Is it all written, is it all locked in? Is there still stuff to write?'

James them replied: 'It's written right but now we're doing rewrites. So we have to, we have to remove some time, we have to change some bits around. 

'So we've been doing that, it's quite tough because Ruth Jones's (Nessa) in Sister Act over in the West End at the minute, and I'm doing The Constituent at the Old Vic.

'So we've been doing quite a bit of writing in dressing rooms and things like that. And then both looking at each other being quite tired from the plays but we'll be back at it tomorrow. 

'Back at it Friday. I hope by Friday… it will be done and finished this Friday!'

Jordan then said: 'This Friday? Is that the deadline?'

James then quipped: 'Well it's the deadline we've set ourselves, because we start shooting pretty soon now. It's not far away now.'

It comes after Gavin & Stacey star Rob Brydon revealed that the show's much-anticipated Christmas finale will 'wrap up' all of the show's long-running storylines.

Speaking recently on Heart Breakfast with Jamie Theakston and Davina McCall, Rob admitted that he and much of the cast are yet to see the full script for the festive special.

Creators James and Ruth confirmed last month that the script was nearing completion, with BBC bosses recently saying that even they are yet to see the story for the final episode, over fears it could be leaked.

Quizzed about the upcoming episode, Rob jokingly quipped: 'Having read it, they handled Bryn's funeral really sensitively! I was worried I wasn't going to be in it, but they've got loads of flashbacks!'

On a serious note, the comic added: 'Do you know what, I know some of the stuff that happens, but I don’t think any of the cast have seen the script yet. 

'They told me one or two little bits of bobs had happened, and I believe it does wrap it all up.'

Rob is expected to reprise his role as Stacey's beloved Uncle Bryn in the comedy, with fans hoping they'll finally learn the truth about what went on during the infamous fishing trip.

James and Ruth have gone to such extreme lengths to prevent leaks they haven't even let the BBC's Director of Comedy Jon Petrie read the completed script.

In a bid to stop any plot details ruining the sitcom's one-off finale, the writing pair, who also star in the show, have only shown the script to a 'very, very tight circle.'

And not even Petrie has made the cut, despite him commissioning the episode as the BBC's big draw for this year's Christmas schedule.

'I genuinely still haven't seen the script, James and Ruth won't let us look at it yet,' he said at the BBC's comedy showcase.

'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.'

Petrie said the real challenge will come when filming starts as it's such a high profile show and recognisable cast that people in the filming locations will be able to spot them.

'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,' he said.

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

Despite having not seen the script, Jon said James and Ruth have come up with a 'brilliant idea and a brilliant story.'

James and Ruth reunited to pen the tightly-guarded new script after the former Late, Late Show host moved back to the UK after eight years living in Los Angeles.

Main characters Mathew Horne, 45, and Joanna Page, 47, will return, alongside series regulars Rob Brydon, 59, Alison Steadman, 77, and Larry Lamb, 76.

The Bafta-winning comedy originally aired for three seasons between May 2007 and January 2010 and returned on Christmas Day 2019 with a special episode.

A ratings hit for the BBC, an impressive 18.49m people tuned in to watch the episode which ended with Ruth's Nessa professing her love for Corden's Smithy and getting down on one knee.

The most-watched scripted programme of the decade, fans were left wanting more as the episode ended before Smithy's reply.