WATCH: Tegan, Sara, and a Super Cute High School Choir Perform "I Was a Fool" on Conan

When we were in high school, being in choir meant singing at graduation. For the kids at Los Angeles' Grand Arts High School, it meant jamming out with Tegan and Sara as they sang "I Was a Fool" last night on Conan. Jealousy aside, the teens do a stellar job and Tegan and Sara, as always, steal our hearts yet again. It's truly been a great week for Tegan and Sara fans. On Monday, the 10th anniversary of So Jealous, the twins announced they'd be releasing  Jealous X, a book detailing the making of their hit fourth album and the success that followed. The book will also included three discs of new content included remixes, b-sides, demos and covers and will be available for pre-order starting in December, so your holiday shopping just got a whole lot easier! But until then, check out Tegan and Sara's Conan performance right here: