Longtime surname on late-night TV (6)

(Other definitions for obrien that I've seen before include "Flann -, Irish novelist" , "Conor Cruise, Edna, Flann or Vincent" , "Kate . . . . . ., Flann . . . . . . (1'5)" , "'Kate ..., Edna ..., (1'5)'" , "I be Ron, strangely, with this surname" .)