Fred Armisen Does Ira Glass Impression On Un-Aired 'SNL' Dress Rehearsal

This weekend, Fred Armisen will co-host a special episode of This American Life with Ira Glass called "Doppelgängers." Armisen's amazing impression of Glass has never actually made it onto SNL, but he did do it alongside Seth Meyers on Weekend Update in this un-aired dress rehearsal segment.