Rewind·Posted on Feb 13, 201821 Celebs You Totally Forgot Made Guest Appearances On "Will & Grace"I mean, who wouldn't want to be Madonna's roommate?by Chris PeñaBuzzFeed ContributorLinkFacebookPinterestTwitterMail 1. Madonna played Liz, an office worker-turned-Karen's roommate: 2. Victor Garber played Peter Bovington, an actor who Jack hires to help spread buzz about his new show, Jack Talk: 3. Dylan McDermott played Tom, who meets Will while they're both taking care of their moms: 4. Rosie O'Donnell played Bonnie, the mother of Elliott, Jack's son: 5. Macaulay Culkin played Jason "J.T." Towne, Karen's divorce lawyer: 6. Geena Davis played Janet Adler, Grace's older sister: 7. Britney Spears played Amber-Louise, Jack's new co-host on Jack Talk: 8. Ellen DeGeneres played Sister Louise, a nun caught up in a sketchy car sale: 9. Edie Falco and Chloe Sevigny played Deirdre and Monet, expert house-flippers: 10. Glenn Close played Fannie Lieber, famed photographer who photographs Will and Grace: 11. Seth Green played Randall Finn, former child star turned talk show host: 12. Neil Patrick Harris played Bill, a "former" gay man attempting to convert Jack: 13. Wanda Sykes played Cricket, Karen's makeup artist: 14. Kevin Bacon played himself, with Jack as his new assistant: 15. Michael Douglas played Detective Gavin Hatch, who helps Will track down his laptop: 16. Mira Sorvino played Diane, Leo's ex-girlfriend who quickly causes trouble in paradise: 17. Luke Perry played Aaron, a self-certified bird enthusiast and Jack's potential love interest: 18. Jason Biggs played Baby Glenn, a celeb from the '80s: 19. Kristin Davis played Nadine, Vince's BFF: 20. Will Arnett played Artemus Johnson, a professional backup dancer: 21. And Sharon Osbourne played Nonny, a friendly bartender: