Jim Beaver (Bobby Singer) eons ago in an episode of "Unsolved Mysteries"

[ljs_lj]

Wikipedia says he's been working on a biography of George Reeves (of 1950s Superman fame), so my eyes are not deceiving me!

Unsolved Mysteries: Who Killed Superman?
http://www.youtube.com/watch?v=b84-PI_7FiM

Jim Beaver's part starts around the 8-minute mark and continues at least a minute.