Flavorwire

This week, the long-running WB-turned-CW drama Smallville airs its two-hour series finale. No doubt the most anticipated moment of the episode will be the return of Michael Rosenbaum reprising his role as Lex Luthor. The actor, who left the series in 2008, finally decided to come back due to the intense outcry of fans, who lobbied long and hard for the bald villain to bid adieu before Clark Kent flew off the airwaves forever. There are a variety of reasons why actors return to shows they had departed, including wrapping up storylines and honoring the series that launched them into stardom. Here is a look back on other actors who came back for the swan songs of their respective series. (Needless to say, there are spoilers ahead.)

1. Shelley Long on Cheers

In its early seasons, Cheers was defined by the electricity of Sam and Diane’s will-they/won’t-they relationship. Long left Cheers midway through its run to be a movie star — a move to be echoed again and again by TV actors with mixed results — only to end up making a string of flops. She returned for the show’s finale to see if there were still sparks between her character and Ted Danson’s Sam. Of course there was, to the extent that Sam hopped on a plane with Diane to go with her to LA. But in the end he remained loyal to his true love, his bar, just in time to bid a graceful goodbye to the audience in the closing moments of the show.