Here's a feather in WB's cap: Julia Roberts will serve as an executive producer of the Frog net's first made-for-TV movie, Samantha: An American Girl Holiday. Set in 1904, the period film is based on the popular American Girl dolls and books, and stars 10-year-old actress Annasophia Robb (Because of Winn-Dixie, Charlie and the Chocolate Factory) as Samantha and Mia Farrow as her granny. Holiday airs Nov. 23.