On the episode where Smithy goes AWOL after learning he's to be a father, Gavin, Mick and Bryn go searching for him in the car. They decide to visit the drive-thru where Rudi works to see if she has any idea. Before Rudi comes over to the window, there is a big woman who calls for her. This woman is James Corden's (Smithy's) sister in real life. She's called Ruth, which is also Smithy's sister's name (Rudi is her nickname).