Ruth Jones says she still views herself as a 'new writer'
The co-writer of the acclaimed comedy Gavin and Stacey says the "pressure is on" as she starts work on the third series.
Ruth Jones, who also stars as Nessa in the BBC3 award-winner, is preparing to sit down with her fellow writer James Corden to pen the next series.
Porthcawl-born Jones said the scripts should be finished by the end of March.
"We only have a short space of time to write it so the pressure is on," she said.
Jones was speaking at the launch of the Royal Court's Young Writers Festival, of which she is patron.
"People have been so lovely and kind about the series but I can't help thinking nothing lasts forever," she added.
"Part of me is waiting to disappoint - that's probably the Welsh pessimism in me."
She also confided to the audience that she still viewed herself as a new writer, with the insecurities that can bring.
"It's about confidence, especially with writing," she explained.
"With acting you are a little bit protected, you have other actors with you as well as the writer and the director.
"But when you've written something it's such a fragile and lonely process. You are never quite sure how it's going to be perceived."
James Corden and Ruth Jones in character as Smithy and Nessa
Jones said she expected work on the new scripts to be more or less a nine-to-five job over the coming months, as she and Corden mapped out the series.
The third series was first announced by the two writers at Jones's BBC Radio Wales roadshow in Barry Island, where half the comedy is set.
Jones said she and Corden, who plays the character Smithy, made a "great team".
But she refused to give any hints as to what the characters in Gavin and Stacey faced in the series.
However, she revealed: ""We've always known how it's going to end, it's a good thing to know where you're heading to.
"And knowing the characters so well makes it somewhat easier. It's a really enjoyable process."