Gavin and Stacey co-creator Ruth Jones has said news leaking early about the show's final episode was "really mean".

Jones and fellow co-creator James Corden confirmed earlier this month that the hit comedy series would return for a one-off episode on Christmas Day.

But rumours of the show's return were first reported by the US news outlet Deadline in February.

"James and I wanted to give everybody a nice surprise and I think it was really mean that they leaked it," Jones told BBC Radio 4's Woman's Hour.

"Because also it meant that I had to lie to people, to friends and family, because they were all saying 'is it happening?'

"And the reality is that until you have your cast booked, budget worked out, all of those things, you cannot say categorically that it is going to happen."

The latest episode of Gavin and Stacey aired on Christmas Day in 2019.

Viewers were left on a cliff-hanger after Jones' character Nessa proposed to Smithy, who is played by Corden.

Jones said she was "so thrilled" by how much people loved the show.

"We'll have had five years away from it and people still seem to be excited and it's a real compliment," she added.

Jones, who is currently starring as Mother Superior in Sister Act on London's West End, described the moment she and Corden came together to confirm Gavin and Stacey's final episode.

"We took a photo in my dressing room in the Dominion Theatre, because James is rehearsing for a play, I'm in Sister Act in the night, so the only time we had was this 20 minute window!

"He had to come to my dressing room after rehearsals and took a picture of us with the script and that was literally the first day we were actually able to say 'yes it's happening'. So we told [the public] when we knew for sure."

Asked what she would miss the most about Nessa, Jones said there was "so much" that she loved about the character.

"Mainly that she really does not care two hoots what anybody thinks. Never did, never will, and I love that about her," she said.

"She's always there - I often use little Nessa lines if I want to divert somebody.

"Usually, if I want to tell somebody to back off!"

Jones said her first foray into musical theatre involved a familiar face - none other than Rob Brydon, who plays Uncle Bryn.

Jones and Brydon both attended Porthcawl Comprehensive School as teenagers, where they first met.

"I used to do [musical theatre] at school... Rob Brydon and I were in several musicals together," she said.

"It must have been quite a challenge having me and Rob in the same show!"

Jones said she was initially unsure about taking on the role of Mother Superior in Sister Act.

"I turned it down initially because I just thought, 'oh that's not me'. And when I think about the people who played Mother Superior before, Sheila Hancock, Maggie Smith... it's a very specific performance.

"I just thought, well everybody's English and quite RP (received pronunciation), and I just didn't feel it was me, so I didn't really automatically think I was ideal casting for it.

"But they were so open to me interpreting it in my own way. I said, 'can I do it Welsh?'"

Jones said she drew inspiration from the many links between Wales and Pennsylvania, the USA state where Sister Act is set.

"My Mother Superior, she moved to Philadelphia 30 years ago, but she's still got her [Welsh] accent," said Jones.

"I end up putting my feet up on the desk... and you'll see that I'm wearing a pair of Welsh flag socks, which often gets a cheer from the Welsh contingent in the audience!"