His daughter, Lennox is the voice of Grogu aka Baby Yoda from The Mandalorian. She was born during production of season 1. Jeff was editing and had been trying to add vocal sounds for the Child but nothing was really working. After several failed attempts from skywalker sound, Jon Favreau noted that the character needed a human baby vocal component in order for the audience to relate to it. So Seibenick started recording his newborn child on his phone and started cutting it into the episodes. Favreau and Dave Filoni were satisfied with the sounds, Jeff kept recording and cutting them in, everyone got so used to it that she ended up staying in as the voice of Grogu.
