There are multiple artists with this moniker:
1) Twin Sister (now known as Mr Twin Sister) is a band based in Long Island, New York formed in 2008. Andrea sings, Bryan plays the drums, Eric plays guitar, Gabe plays the bass, and Udbhav plays keyboard. After releasing two EPs ('Vampires with Dreaming Kids' and 'Color Your Life'), the five-piece released their debut album 'In Heaven' on September 26 via Domino Records.
2) Twin Sister was "the self-proclaimed greatest Star Wars funk band." Read more on Last.fm.