Britney Spears will help "Teen People" celebrate its second anniversary by appearing in a series of nationally syndicated TV spots which are scheduled to begin airing on December 27.The singer, who just turned 18, will also serve as the cover girl for the anniversary issue of "Teen People." Dated February 2000, the magazine will actually arrive on newsstands the same day Britney's commercials hit the airwaves. The teen star has enjoyed a breakout year in 1999, as her debut album "...Baby One More Time" has been certified nine-times platinum by the RIAA since its release in January. Spears has just released a new home video, titled "Time Out With Britney Spears," which collects her first three music videos as well as some behind-the-scenes, day-in-the-life footage of the singer. For more on the teen star's current projects, check out the MTV Online feature "Britney Spears: Britney's New Moves."