Media playback is unsupported on your device Media caption James Corden speaks to the BBC's Colin Paterson about being back in Barry Island and why he decided it was time for a reunion

Oh! What's occurring? Christmas on Barry Island, that's what. Ten years since we left the fab four - Gavin, Stacey, Nessa and Smithy - on the Welsh seafront, they're back with a festive special that will have you cackling over your Christmas pudding and blubbing into your Babycham. Probably at the same time.

Image caption Christmas Eve down the pub hasn't changed much

We sat down with Ruth Jones, James Corden and the rest of the gang to find out how the episode came about a decade on, how our favourite Welsh/Essex couples are finding parenthood and if we'll ever find out what happened on THAT fishing trip.

A logistical nightmare

Geography - not to mention James's hugely successful US gig as the host of The Late, Late Show - was "a big problem in getting the show off the ground," explains Ruth, who plays Stacey's closest friend Nessa.

"James and I live on different continents. We wanted to be sure if we did bring it back that it was good. Ever since it finished, James and I have always secretly texted each other lines for the characters."

James, who plays Gavin's best friend Smithy, explains: "We'd send each other little things like, 'I just heard someone say this in the supermarket today and I think it's something Pam would say.'

"There was very much a feeling of the time to do it is when you don't need to."

Image copyright Getty Images Image caption Corden is now a big name across the pond

But they still had to find that time.

Ruth says: "James does a show every day so he had to double record the show - I went to LA for a long weekend and mapped the story, then had a week in LA in February, writing."

However, even after sorting out the logistics, the writing didn't come easily at first.

"We got to the end of the week and there were times when we thought: 'This isn't happening,'" she says.

"We argue, we have a brother/sister relationship. [But] our friendship is so strong."

Media playback is unsupported on your device Media caption BBC Breakfast were the only people invited on set during filming, back in July, during a heatwave

Then there was just the small problem of getting the cast back together after a long hiatus.

"We were so lucky, James gave up his summer holiday to come over, to find out if everyone was available - it was a miracle, we found a two-and-a-half week period. It felt like a good luck omen.

"James and I contacted half the cast each. [They were] lovely phone calls to make! Thank God they said yes as we'd written the script by then!"

Getting hold of the actors wasn't straightforward…

Image caption The fishing trip question just won't go away...

Joanna Page, who plays Stacey, proved particularly elusive.

"Ruth got in touch with me using every form [of communication] - and I'm not very good at getting back in touch. I didn't respond for a bit, I was busy with the kids. I'm the mother of three children! [When I saw the messages asking me to call her] I thought, 'This is either something really good or it will be dodgy photos but why would they go through Ruth?!'"

Ruth's persistence finally paid off.

"I was so excited waiting for the script," says Joanna.

"I was sat in the car park reading it, emailing Ruth and James, quoting their lines back at them!"

Robert Wilfort, who plays Stacey's brother Jason, was sceptical when he first got the call.

"When James rang from LA, I thought it was a scam from some Nigerian prince!" he jokes.

"I didn't even tell my mum. Everyone else was reorganising their schedules [for filming] but I was unemployed so was just pleased to have a job!

James also had to call Melanie Walters, who plays Stacey's mother Gwen, four times as she also thought it was a scam: "I didn't recognise the number!"

And then they all got the jitters…

Image caption The Sutcliffes pop round to Pam (Alison Steadman - third from left to right) and Mick's (Larry Lamb - left) before Christmas

Larry Lamb, who plays Gavin's father Mick, says: "When James said what was to happen… I thought, can they carry this off? Then three months of not telling anyone, [just] lying! Now I've seen it I feel extraordinarily overcome with emotion. You turn up at rehearsal and you feel scared. But it's everything you hoped it would be and more."

Joanna, who had taken time out to raise her children, says she asked herself, "Can I even act anymore?" while Matt Horne, who plays Gavin, also felt nervous at first.

"Ruth asked me and my initial reaction was relief - I'm so glad James has got some work!," he jokes, referring to his cast mate's Stateside success.

"Then the nerves kicked in. The script is brilliant. It's the best episode we've ever done, it's sensational. After day one, everything settled down and the nerves went. All the actors love each other, we have a great time and it comes across on screen. It's really easy to act around really great actors - Jo went to Rada!"

Rob Brydon is chief minister of fun

Image caption Nessa and Uncle Bryn just love a duet

Ruth says: "We began rehearsing in June, it was like a family getting back together again. It went so smoothly and it was such fun. Rob Brydon is responsible for a lot of the fun.

Rob, who plays Stacey's Uncle Bryn, has one abiding memory from filming, some of which took place during a heatwave.

"It was so hot! Bryn's trousers and jumper are 100% polyester, the tie is 100% polyester, the shirt was the same and I was sweating!

"It's the happiest job I've ever done. Joyous. I had tears in my eyes watching it back. I'm thrilled."

That's lovely Rob but what ACTUALLY happened on that infamous fishing trip?

"I don't know, they've never told me!" Grrrrr.

Margaret is much missed

Image caption Margaret John played one of the show's best loved characters

Margaret John played Gwen's sweary elderly neighbour Doris in the original series but the actress sadly died in 2011.

Melanie says: "The art department gave me a picture of Margaret and myself with huge orange coats on reading the paper and I put it on the table for the read-through so she was with us."

Without giving too much away, Doris is very much gone not forgotten in the Christmas special.

Ruth explains one particular scene: "Maggie was such a special woman, incredibly talented and we wanted to pay homage to her, to raise a glass and undercut it as Doris, as a character, was rude. I think Maggie would have loved it.

"The biggest sadness was not having Doris there. She was an auntie to everyone."

The pressures of parenting

Neil the Baby isn't a baby anymore. And Gavin and Stacey have also become parents (let's just say there's a nod to Pam's love of the Royal Family in the baby names).

Ruth says: "I absolutely adore Nessa. I feel brave and so at ease playing her. It's liberating playing her.

"You can see how she's developed into a mother, a lovely mum [but] she's retained her Nessa-ness.

"It would have been easy to make the young Neil a tough bad boy but we chose not to do this. We wanted to tap into Nessa's softer side."

One of the key themes of the show is one many couples with children will be familiar with. How do you make time for each other, keep your relationship strong and maintain intimacy when raising young kids is so all-consuming?

Ruth says: "Gavin and Stacey are the heart of this show, we wanted to tell their story 10 years on.

There's one particular scene just featuring the couple which Ruth said she was particularly "chuffed with… every time I watch that scene, I cry, I get goosebumps".

Joanna concurs: "It's so beautiful, the first time I read it, I cried… after that scene we just had fun and lots of gin."

Having a family now herself, she jokes that: "It's art imitating life - this is what my life is like right now. But I do have a very healthy sex life!"

Not enough room at the inn

Image caption What will the fans think?

Sadly, you won't be seeing every character in the new episode - but there may be some new faces.

"We were very lucky to have such a huge cast in the past but we had to think about what would work best for the storyline," explains Ruth.

"But there was very little that we cut. Gavin and Stacey looking at photos of the kids in Nativity went. But the BBC were very kind, it was meant to be an hour, it's a little bit over but they said that's fine."

Are they worried about the reaction?

James says: "People might watch the special and think that was awful, why did you ruin it? And that's the pressure of it."

But is this the final curtain?

Ruth doesn't rule it out.

"There are no plans but obviously there is room for it to move on, so who knows?"

Gavin & Stacey is on BBC One on Christmas Day at 2030 GMT.