Melanie Walters, who plays Gwen West in Gavin and Stacey , was left red-faced after a hilarious mishap during filming for the show's Christmas special. The cast reunited last year for the final ever episode, which resolved the cliffhanger between Smithy (played by James Corden) and Nessa (portrayed by Ruth Jones), ending a five-year suspense. In a behind-the-scenes blunder, Melanie recalled undressing, not realising that the cameras were still capturing every moment. If that wasn't awkward