Seth MacFarlane stopped by Jimmy Fallon's "home" version of The Tonight Show the other night and was challenged by Jimmy to sing "You're Nobody Till Somebody Loves You," except there was a catch... Seth had to sing the song in whatever voice Jimmy held up on a flashcard. The result? PURE MAGIC! Seth-voiced characters from Family Guy and American Dad were in there, including Peter, Brian, Stewie, Quagmire, Stan, and Roger, plus Kermit the Frog and Liam Neeson impressions made an appearance as well!