37 Glee Guest Stars You May Have Forgotten All About

Idina Menzel played Shelby Corcoran, Rachel's birth mother and the coach of Vocal Adrenaline. When these two talented ladies hit the stage together, the vocal magic is palpable. In a meta moment from season six, Rachel sings "Let It Go," Menzel's ubiquitous hit from Frozen.

Kathy Griffin had a guest spot on Glee playing a politician who is a judge at Regionals. The lovely Loretta Devine also played a judge at the same event named Sister Mary Constance.

While we love Mr. Schuester, it's hard not to fall in love with John Stamos's character Dr. Carl, aka Emma's ex.

Lovato turns up several times in Glee's fifth season as Dani, Santana's coworker/girlfriend.

Banks played a modeling agency representative who tells Sam that he has potential, but that he'll need to lose ten pounds to have a career.

Shannon appeared way back in season one as McKinley High's astronomy teacher/badminton coach.

Newton-John appeared as a fictional version of herself in the episode "Bad Reputation" during season one. She asks Sue to help recreate her infamous "Physical" video.

Matt Bomer made an appearance on Glee as Blaine's big brother. He shows off his musical chops during a Duran Duran mashup performance and "Somebody I Used to Know."

Jackson starred as the coach of Vocal Adrenaline during seasons two and three.

Harris pops up as McKinley High board member Bryan Ryan, who has a long-standing feud with Mr. Schuester.

Ricky Martin initially helps bring a little authentic Latin flavor to New Directions, but he's later offered Mr. Schuester's job as Spanish teacher.

Katie Couric isn't afraid to ask the tough questions when she made a cute cameo on Glee to interview the sneaky Sue Sylvester.

Estefan shows up twice as Santana's mother; first in season three, then again in season six when Santana marries Brittany.

Lohan appeared in a "comeback" appearance as a judge on the "Nationals" episode.

Hilton also appeared as himself on the "Nationals" episode, alongside Lohan and Rex Lee.

Broadway star Jonathan Groff plays Jesse St. James, a handsome bad boy with a killer voice, who gets Rachel to fall for him before popping up again as the coach for Vocal Adrenaline. In the series finale, the time jump reveals the two are married.

The Real Housewives of Atlanta personality NeNe Leakes plays Roz Washington, a former Olympian who becomes a tough, sassy synchronized swimming coach at McKinley and later, the coach of the Cheerios.

The legendary Carol Burnett brought her talents to Glee as Sue Sylvester's mom.

Along with Billy Dee Williams and Tim Conway, Squibb guest starred as a resident of a retirement home who Kurt helps with a production of Peter Pan.

Filipino singing sensation Charice made her Glee debut during season two as Sunshine Corazon, a foreign exchange student whose talent gives Rachel a run for her money.

Kristin Chenoweth has shown up a few times on the show as the racy April Rhodes, a former member of New Directions who went to school with Mr. Schuester.

During the very first season of Glee, actor Victor Garber played Mr. Schuester's father.

The talented Josh Groban played himself on Glee. To everyone's surprise, he seems to have a thing for Mr. Schuester's tipsy mom.

MacLaine appeared as June Dolloway, a New York socialite, in season five. She and Blaine rock out to "Piece of My Heart."

Rapper Eve took a no-nonsense approach to her role as the Jane Addams Academy show choir director Grace Hitchens.

Who could forget Kate Hudson's guest arc as Rachel's harsh dance teacher, Cassandra July, at NYADA?

Gwyneth had a recurring spot on the show as the laid-back, fun-loving substitute teacher Holly Holiday. One of our favorite moments from Paltrow comes during her "Umbrella" mashup.

Jeff Goldblum played one of Rachel's very supportive dads.

Whoopi Goldberg guest starred on Glee as a NYADA representative.

New York fashion icon Parker appeared in season four as Vogue editor Isabelle Wright, who takes Kurt under her wing.

Twilight's Peter Facinelli had a recurring role as the director of Funny Girl, the play in which Rachel scores a part during her time in New York.

LuPone guest starred as herself on the second season finale.

Sons of Anarchy star Sagal appeared as Artie's mother, Nancy, in season four.

On Glee's season three finale, Lipton appeared as himself.

While her appearance is super short, we loved when Britney Spears pops up in a few of the students' fantasies during her tribute episode.

Hamlin appeared in season six as Kurt's older gentleman friend.

The former American Idol contestant appeared in the sixth season as an NYU student named Elliott who joins Kurt's band.