Stefan "Stee" Gfeller, born 3 November 1987, is the Zibbz duo's drummer, keyboardist, and producer. From 2003 to 2007, he studied music in Winterthur where he completed his SMPV Diploma. Outside of Zibbz, Gfeller also worked as a drummer and producer for a range of different artists, including Gölä and Bastian Baker. Furthermore, Gfeller is a member of the punk drum collective Street Drum Corps.