"Glee" definitely packed in the star power during its six seasons of musical melodrama.
Since the Fox series raised its curtain in 2009, full episodes have been devoted to the repertoires of Michael Jackson, Fleetwood Mac, Lady Gaga and Madonna, among others. On one occasion, a recording artist who was being spotlighted made an appearance on the tribute episode (we're looking at you, Britney Spears). But often, the pithy guest stars outshone the performances and doled out some memorable moments of their own.
As we say goodbye to McKinley High School (and the series' awkward post-graduation story lines as well) on Friday night, here's a look back at some notable "Glee" guest stars.
Britney Spears: The "Toxic" singer appeared in 2010's "Britney/Brittany" episode, which had Cheerio Brittany S. Pierce (Heather Morris) undergoing a hallucinogenic visit to the dentist. The pop star also served as a writer on that episode, as well as on a 2012 episode titled "Britney 2.0."
Gwyneth Paltrow: The Oscar winner played funky substitute teacher Holly Holliday in five episodes and stepped in as the New Directions glee club's temporary director while Will Schuester (Matthew Morrison) was out sick. Paltrow also surprised a New Jersey audience during the "Glee Live! In Concert" arena tour in June 2011, belting out Cee Lo Green's "Forget You," as she had done on the show.
Adam Lambert: The "American Idol" alum had a five-episode arc during Season 5 as Elliott "Starchild" Gilbert, an NYU student who auditioned for Kurt Hummel's (Chris Colfer) cover band. Pamela Lansbury then created the offshoot group One Three Hill with him and waitress Dani (four-time guest star Demi Lovato).
Idina Menzel: The Tony Award winner -- who bears an uncanny real-life resemblance to "Glee's" Rachel Berry (Lea Michele) -- appeared on the show ahead of her "Frozen" glory in the role of Rachel's biological mother, Shelby Corcoran. Rachel and Shelby's "I Dreamed a Dream" still gives us chills, as does Rachel and Kurt's belted-out take on "Wicked's" "Defying Gravity" -- though that one imparts a very visible shudder when Kurt throws the final note.
Kristin Chenoweth: Menzel's "Wicked" costar showed up on the series after pleading for a part on the show during her 2009 Primetime Emmys speech. Chenoweth played McKinley High legend April Rhodes in about five episodes that showed her downward spiral after she failed to make it big.
John Stamos: After being introduced to the show as Britney's hunky dentist, Dr. Carl Howell, the "Full House" alum memorably twirled his female castmates around the rehearsal room as he sang MeatLoaf's "Hot Patootie -- Bless My Soul" from "The Rocky Horror Picture Show." The character was also love interest to school counselor Emma Pillsbury (Jayma Mays) and tried to help her work through her OCD tendencies.
Carol Burnett: The reason track-suit enthusiast Sue Sylvester (Jane Lynch) became the taskmaster we've come to know and love can be attributed to the cheer coach's estranged mother, Doris Sylvester, played by Burnett. The five-time Golden Globe-winning actress made two guest appearances as the purported Nazi hunter and doled out a series of belittling insults in the manner of the rival Vocal Adrenaline coach who normally issued each episode's requisite zingers.
Whoopi Goldberg: "The View" host appeared in the same episode as Burnett (as do Geraldo Rivera and Michael Bolton). Goldberg did six episodes as Carmen Tibideaux, the intimidating dean of vocal performance and song interpretation at the New York Academy of Dramatic Arts. However, any hope of the theater veteran whipping out her "Sister Act"-inspired nun's habit was squelched during her run on the show.
Kate Hudson: Hudson debuted as NYADA's unrelenting dance instructor Cassandra July during the Season 4 premiere and stayed on for five episodes. The "Nine" star's character had turned to teaching after having a meltdown during a performance of Broadway's "Damn Yankees" and later encourages students to "suffer from severe body dysmorphia" to show their commitment to showbiz.
Ricky Martin: The Latin pop star's character finally brought up a realization that should have been obvious from the get-go: Will Schuester shouldn't be teaching español. Martin's David Martinez stepped in for Will as McKinley's language instructor but not without throwing in a musical number. The gyrating performer memorably performed a Spanglish version of LMFAO's "Sexy and I Know It" that probably had no business in high school extracurricular program (though, neither did many of the performances).
Sarah Jessica Parker: Casting directors really didn't have to reach much with this one. The "Sex & the City" alum landed a fashion-inspired role as Vogue.com editor Isabelle Wright, who took a liking to Kurt's fashionable flair. She then enlisted him to give Rachel a much-needed makeover.
Neil Patrick Harris: The "How I Met Your Mother" actor guest starred as Will Schuester's archrival and former classmate, Bryan Ryan, turning up as a school board member who threatened to cut funding for the glee club because it had destroyed his life. Harris, ever the showman and magician, did magic tricks in a "Daydream Believer" flashback sequence that pitted Ryan against Will.
Shirley MacLaine: The Oscar-winning legend popped up in two episodes in 2014 as New York socialite June Dolloway, a meddling benefactor who notably performed a duet with Blaine (Darren Criss) incorporating Janis Joplin's "Piece of My Heart" and "Pippin's" "No Time At All." Yeah, it was one of those questionable pairings that would make sense only on "Glee" -- or during a Grammy Awards telecast.
Who was your favorite guest star? Sound off in comments.