Hilary Norman Peterson is a regular fictional character on the American television show Cheers. The character was portrayed by actor George Wendt and is named Hilary after his paternal grandfather.

Clifford C. Clavin, Jr. is a fictional character on the American television show Cheers played by John Ratzenberger. A postal worker, he is the bar's know-it-all and was a contestant on the game show Jeopardy! Cliff was not originally scripted in the series' pilot episode, "Give Me a Ring Sometime", but the producers decided to add a know-it-all character and Ratzenberger helped flesh it out. The actor made guest appearances as Cliff on The Tortellis, St. Elsewhere, Wings, and Frasier.