Guest stars can be a good thing... or a bad thing. Some shows handle it better than others, incorporating the usually familiar stars into the episode(s) for maximum effect. The recent turn by Robert Wagner on 'NCIS' was an example of a terrific guest appearance.

Speaking of Robert Wagner, you're probably aware that he starred on the much-loved ABC's romantic detective series 'Hart to Hart' with Stephanie Powers. Now, two other stars will be playing a 'Hart to Hart' type of couple on a current show. Swoozie Kurtz and Fred Willard will be on 'Chuck' later this season as a pair of former spies who were romantically involved. 'Hart to Hart' was mentioned in Michael Ausiello's scoop, and he even went so far as to suggest a spin-off.