Gavin and Stacey star Laura Aikman's involvement in the last ever episode was so top secret that even her own family had no idea she would be in it. Fans tuning in to watch the series final on Christmas Day were gasping over their Christmas pudding when a shock twist showed James Corden's character Smithy was preparing to marry girlfriend Sonia - played by Laura, 39. The last Christmas special that aired in 2019 ended with a cliffhanger proposal where Ruth Jones's Nessa proposed to Smithy, and