The hit show wrapped in 2019, but fans had been hoping that it might make a comeback for some more episodes.
"I’m really hugely complimented that people love it so much," she said. "But it is quite an extraordinary thing… it’s almost like you mention the words Gavin And Stacey and people assume it’s back."
“But it’s not," she added.
Gavin And Stacey aired for three series between 2007 and 2010.
And the last instalment was a Christmas special in 2019.
That ended on a cliffhanger as Jones' Nessa character proposed to Corden's Smithy, but viewers didn't get to hear his answer.
Jones said she didn't mind leaving it like that, saying it was "interesting" to leave it with fans wondering what had happened.
However, Corden previously suggested he would like to do more episodes.
Speaking to Zoe Ball on BBC Radio 2’s Breakfast Show last year, he said: “As it stands right now, there aren’t any plans to do one, but that’s not to say that there isn’t the want or the inclination to do one… that special ends on such a… it’s so open-ended that I think it would be a shame to leave it there."
The TV star added that it "doesn’t feel like the end of a book, it feels like the end of a chapter".
Watch: Gavin And Stacey star Joanna Page expecting her fourth child