Premise: Terry and Julian is a British sitcom that aired on Channel 4 in 1992. Starring Julian Clary, it was written by Clary, Paul Merton and John Henderson. The title is a spoof the title of the long-running BBC sitcom "Terry and June", whose star June Whitfield made a guest appearance in one episode of "Terry and Julian".
Hypothesis: June Whitfield's appearance on Terry and Julian was the only guest appearance she's ever made on a TV show.