They secretly started writing the episode years ago, and after reconnecting at James's 40th birthday in Mexico, they felt the story was still there to explore without pressure.
The show picks up five years after the last special, with Nessa on bended knee proposing to Smithy.
They met while working on the show 'Fat Friends'.
They often shared meals, including dishes from the Crown Plaza menu, and have eaten together more than with anyone else outside their partners.
They wrote in various locations, including hotels, Ruth's house in Cardiff, and James's flat above a Chinese restaurant in Beaconsfield.
They attempted to boil eggs in an ice bucket and later in a kettle, but both methods resulted in a horrific smell, and they eventually gave up.
James's wife, Julia, organized a surprise party in Mexico, and Ruth flew in to join the celebration, surprising James when she walked in.
Gwen, Stacey's mother, often offers to make an omelette in the show, and the reference became a running joke throughout the series.
She loves a straight Dairy Milk chocolate bar with hazelnuts.
She underwent hypnosis and used aversion therapy, associating chocolate with the taste of mushy peas, which she hates.
Oh, what’s occurring? We’ve only got Ruth Jones & James Corden - aka Smithy & Nessa - joining us for dinner! The creators and stars of hit and beloved comedy, Gavin & Stacey popped round to tell us all the exclusives about the upcoming Christmas special and final ever episode. After binging the entire 3 series in a week, I have a lot of questions. We found out that James & Ruth secretly started writing the episode years ago, Ruth loves going on a literary cruise, how they boiled eggs in kettles when travelling, that Ruth surprised James at his 40th birthday in Mexico, how Ruth was hypnotised to hate chocolate, that James is loving living back in London, and you really, really don’t want to miss Nessa & Smithy giving us their ‘last supper’! We are so excited to see what our favourite residents of Barry Island and Billericay have been up to for the last 5 years. The Gavin & Stacey finale will be on BBC1 at 9pm on Christmas Day - oh, don’t miss it! X Hosted on Acast. See acast.com/privacy) for more information.