In the UK it would be a soap star. Soap opera's, are drama series which were originally broadcast to sell products such as washing powder (laundry soap) in the US during the mid 1960's. In the UK we have strict advertising codes during programmes, but commercials (adverts) inbetween and during the shows.

A soapie is normally a tv show (normally drama). It's often on tv five days a week and can run for years and years. Australia has quite a few of them. Most people think they're pretty bad and boring. Having a "bun in the oven" means you're pregnant. Bread baking in an oven rises (in other words, it gets bigger, like the stomach of a pregnant woman - hence "bun in the oven"). I'm Australian, it's quite a common saying here. It's used very informally and is considered slang.