Elton John, Cher, Madonna, Britney Spears, Ellen Degeneres. Will & Grace has guest starred some pretty epic divas.

Curry guest stars as Marion Finster, Karen's husband, Stanley's, mistress' uncle. Keeping track? He pops into Karen's wedding to her fourth husband, who happens to be his brother -- Karen's husband's mistress' father.

Connick plays Leo, a Jewish doctor who rides in on a literal white horse to interrupt Grace from getting artificially inseminated. Leo isn't remembered fondly, as he eventually cheats on Grace (how dare!) and they divorce after only two years.

Cannavale plays Vince, Will's only long-term relationship of the show. They meet when Vince gives Karen Walker a speeding ticket, and Will defends her in court. Cannavale then went on star in HBO's Boardwalk Empire and Vinyl.

Goldblum plays Karen's long-time enemy. After losing student body president to her in high school, Sydney has spent the rest of his life hatching ill conceived schemes to bring her down.

Driver plays Lorraine, Karen's husband's mistress who intensely loathes Karen. Lorraine is a prison cafeteria worker who maintains an affair with him for the majority of the series.

Elliott is Jack's son; the result of donating sperm at 17. Played by successful child actor Angarano (Almost Famous, Lords of Dogtown), Elliot becomes extremely close to Jack, who has just lost his own father. Awww.

Harrelson stars for a short arc as Nathan, Will and Grace's neighbor, who ends up proposing to Grace during sex.

In a super-sized episode, the multi-talented Madonna plays Liz, a young woman Karen takes in as a roommate after she splits with her husband.

Kevin Bacon made audiences laugh out loud playing himself. He mistakenly identifies Will as his stalker, and the two end up dancing the Footloose dance together, much to his actual stalker's (Jack) chagrin.

Before he was saving lives at Seattle Grace Hospital, Patrick Dempsey played Matthew, a sports reporter Will meets at Banana Republic.

Malcolm Widmark is the government agent who helps Karen's husband fake his own death. He even briefly dates Karen to help her with her grief, before admitting her husband is still alive. Oops!

Shannon plays Val, another one of Will and Grace's neighbors, who is a slightly unhinged alcoholic. Her time on the show comes to an end when Jack finds her in his bedroom uninvited.

Acting legend Gene Wilder plays Mr. Stein, a not-so-kind senior partner at Will's law firm, who is later incarcerated and shipped off to a mental facility.

Pop star, dancer, actress Jennifer Lopez stars as herself in a three episode arc. After Jack runs into her, he believes they're best friends. Karen writes a song for her to listen to, but J.Lo has more important things to do. Shocker.

Damon stops by to play Owen, Jack's heterosexual rival, who pretends to be gay in order to be in the Manhattan Gay Men's Chorus. He's eventually outed when Grace successfully seduces him.

In the episode "Me and Mr. Jones," Jones plays a co-star to Jack in an off-broadway production and enrolls in acting classes to learn from him. It doesn't go well.

The singer, the actress, the diva Cher herself gave one of the most memorable cameos of the series when she appears to Jack, her biggest fan, who doesn't believe she's real. After she slaps him in the face, he reconciles that he's just met his idol and is stunned.

Glenn Close pops in to play Fanny Leiber, the show's parody of super famous photographer Annie Leibovitz, who takes a ridiculous photo series of Will and Grace.

Elton John didn't need to put on a persona for his spot on Will & Grace, instead he played himself -- an omniscient figurehead of "the Gay Mafia."

Indie darling Chloe Sevigny laughed it up as Monet, a wealthy bi-sexual real estate agent who falls for Will, much to the dismay of her lesbian partner (played by Edie Falco).

Demi Moore plays Sissy, Jack's childhood babysitter who becomes a temporary nightmarish roommate.

At the height of superstar Spears' fame, she co-starred as Amber Louise, a self-proclaimed "harcore lesbian" and conservative Christian, who guest stars on Jack's show.

Before she was running her own daytime talk show, Degeneres made time to play Sister Louise, a nun who buys Grace's uncle's old car.

It's only fitting that the former child actor would play Randall Finn, an annoying child star who has since grown up .

O'Donnell plays Bonnie, the mother of Jack's biological son Elliott, who is jealous of Jack's openness with his sexuality.

Broadway superstar and icon Bernadette Peters made time to play Ginny, Karen's little sister in the series' penultimate episode.

In the seventh season, Arnett plays Artemus who competes with Jack for a spot as one of Janet Jackson's backup dancers. Spoiler: neither is chosen.

In a wink to the audience, Nick Offerman, Megan Mullally's real life husband, made a cameo as a plumber who Karen has a brief affair with while her husband is in jail.