And apparently, this included creating a special codename for the special, inspired by a misunderstanding between stars Rob Brydon (Bryn) and Alison Steadman (Pam) shortly after both had been enlisted in the episode.
“We were at the BAFTAs, and I was walking to my seat and I saw Alison and I said hello and she said ‘I’m nervous about G&S,’” Brydon told the crowd at a recent Q&A.
“And I thought: ‘Gilbert and Sullivan’. I thought she was there nominated for a performance in a thing about Gilbert and Sullivan. And I might even have said to [her], ‘But you were fantastic in it’.
Get the latest TV and entertainment news direct to your inbox
“And then [my wife] Claire and I went and sat down and I turned around and went ‘Ohhh!’” he laughed.
However, Brydon’s mistake soon caught on, and before long others in the cast were using the handy sobriquet.
“We did set up a WhatsApp group, we called it Gilbert and Sullivan,” Jones noted.
“On my email, I was so scared in case anyone saw it,” added Steadman. “So I called it Gilbert and Sullivan. I said I’d been asked to do Gilbert and Sullivan again.”
This wasn’t the only bit of subterfuge used to keep the special under wraps – at one point while scouting locations, Jones brought her niece to pretend it was a day trip to the old sets – though the star admits she felt bad for lying to so many people about what she and Corden were up to.
“I think the intention was always there, even though I always used to lie in the press and say, ‘No we’re not doing any more’ because until we absolutely knew we had something, there was no point in telling anybody,” she said.
“I went onto the Radio 2 breakfast show the day before it was announced, and I was going on to publicise my book, so I knew that the following day, on the 28th May, we were going to be announcing it, and I was sat there with Matt Lucas who was taking the show that day.
“And he said to me the question that I get asked all the time – ‘Is there going to be more Gavin and Stacey?’, and I went, ‘Oh it’s really difficult because James in America’. [He said] ‘Yeah, but is there going to be more?’ [and I said] ‘Oh it’s so lovely that people love the show so much’.
“It was awful,” she added. “I was like a politician on Politics Live not answering the question, yes or no, and the next day I had to email Matt and say ‘I am so sorry for blatantly lying to you’.”
“The hard bit is not telling anyone about it,” agreed actor Larry Lamb (Mick).
“So I had about three months of that, not only just the usual ‘I don’t know’, but actually lying now.”
Brydon agreed: “Like Larry said, once we knew it was going to happen, I was touring Australia, and they love it there, so I get asked all the time, ‘Will there be more?’ –and it was hard wasn’t it then, because then you’re lying to people.
“Because I’d been going ‘No I don’t think so’ and I had to now go, ‘No I don’t think there will be’ and I thought they could see it in my face that I was lying.”