James Corden has told how the Gavin & Stacey comeback almost didn’t happen.

The much-loved sitcom returns, for the first time in 10 years, with a special episode on Christmas Day.

But when its co-creators Corden, 41, and Ruth Jones, 53, first secretly reunited to bring back the show it almost did not get off the ground.

Corden, who plays Smithy, told The Sun: “In a 24-hour period the show was dead, then brought back to life. It was deeply depressing…

“There was a very real moment where we had written maybe 40 pages… And we both finished, and Ruth went, ‘What do you think?’ And I said, ‘We haven’t got it. It just doesn’t feel like Gavin & Stacey’.

“We decided, ‘OK, well, thank goodness we didn’t tell anyone.”

James Corden, Joanna Page, Mathew Horne and Ruth Jones James Corden, Joanna Page, Mathew Horne and Ruth Jones (Tom Jackson/GS TV Productions Ltd/BBC)

The pair were holding a “post-mortem” about their efforts when an idea “landed in the room”.

Corden said: “It’s probably the quickest scene we’ve ever written. And I think it’s the best scene Gavin & Stacey has ever had.”

Jones, who plays Nessa, previously told how the pair thought “let’s just give up because there was something missing and I couldn’t pinpoint it”.

But she said: “We had dinner with our partners, and we got talking, something sparked something off…

“Out of the blue we just got this idea and I think that was the heart of this Christmas special.”

The Gavin & Stacey Christmas Special airs at 8.30pm on BBC One on Christmas Day.