Smithy, Gavlar and the gang are coming back to screens on Christmas Day, but the co-stars have been plagued by feud rumours.
But Mathew, who plays Gavin alongside James’ Smithy, has insisted it was all lies.
He told MailOnline that the claims were “made up” as he was asked if he felt the need to address the rumours of a feud between him and James.
After the last episode aired in 2010, the pair continued to work together on film Lesbian Vampire Killers, which was panned by critics, and their comedy show Horne and Corden.
After that, James moved to LA and landed his job hosting The Late Late Show, which propelled him to A-list status.
Fans had been dying for the show to return for years, but even some of the cast members admitted they didn’t believe it was really happening when James and his co-star and co-writer Ruth Jones, who plays Nessa, called them.
Robert Wilfort, who plays Stacey’s brother Jason, and Melanie Walters, who stars as Stacey’s mum Gwen, said they ignored the calls, thinking they were nothing but pranks.
Robert said: “I got this call from Los Angeles, it was James but I thought it was a scam, like the Nigerian prince trick or something.”
Melanie added: “James text me. And the way he phrased the text was, ‘It’s James Corden here Mel, you may remember me’. I just thought I was being trolled. I just completely ignored it…
“Then he rang and it was a weird number, and so I completely ignored it again. It was around the fourth time, he actually left a voicemail, and I finally realised it was him…
“Ruth just got in touch with me on every form of social media, email, message, everything. And I’m not very good at getting back in touch with people, I’m absolutely terrible. So I didn’t respond for a bit because I was busy with the kids.”
* Gavin and Stacey returns on Christmas Day
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