Ted Danson
Frasier was a spin-off of another successful show, Cheers, so it was exciting when the sister show's cast members made an appearance, including star Ted Danson as barowner Sam Malone.
Shelley Long
Another Cheers star, Shelley Long's Diane, the bar's popular if condescending waitress, swung through the sister show, too.
Woody Harrelson
The Cheers bartender was on Frasier in a season six episode that taught Frasier he had moved on from his former life.
Teri Hatcher
The Desperate Housewives star plays Marie, who Frasier dates until he starts to suspect she's in their relationship for the free psychiatry advice.
Bill Gates
Widely considered the show's most fun guest star, the tech titan appeared on an episode as a version of himself who, once Frasier's audience realizes is at the radio station, has to handle a flood of calls from listeners as to how to install their Windows software.
Tony Goldwyn
While he only was featured in one episode, Tony Goldwyn's character Roger made a big impact on the show as Roz Doyle's (Peri Gilpin) boyfriend. Initially, Roz was embarrassed by Roger's profession as a garbage man, but realized he was a great partner when she saw how sweet he was with her daughter.
While the characters eventually broke up, Roger was often referred to off-camera past Goldwyn's episode, and the charisma he channeled into the part was present again when we saw him as one of the main characters in Scandal.
Rita Wilson
The iconic actress played Frasier's mom and also had a short stint in the same role in Cheers.
Laura Linney
The actress plays Charlotte, one of Frasier's more lovable girlfriends, and serves as a major plot point of the show's finale as when Frasier leaves Seattle, it's revealed he is going to Chicago to try to win her back and have his happily-ever-after.
Patrick Stewart
The X-Men alum plays Alistair Burke, an opera director who has an unrequited romantic interest in Frasier.
Michael Keaton
The A-lister plays Blaine Sternin, Frasier's ex-wife's half-brother who is wheelchair-bound, and who Frasier suspects of pulling a con on everyone.