5 Celebrities You Forgot Guest-Starred On The Simpsons

When "The Simpsons" transitioned from short segments on "The Tracey Ullman Show" to a standalone animated series, it quickly became an international sensation and soon had celebrity guest stars lining up to make an appearance.

Over almost 40 years, "The Simpsons" has featured an impressive roster of celebrity appearances. Among the stars who have appeared on the animated sitcom as themselves include "Star Wars" star Mark Hamill, former U.K. Prime Minister Tony Blair and the band Green Day, who were seen in the opening of 2007's "The Simpsons Movie."

A number of celebrities have also joined the cast of "The Simpsons" as original characters. Willem Dafoe has appeared as both the Commandant of Rommelwood Military School and Bart's (Nancy Cartwright) strict new teacher Mr. Lassen. Jeff Goldblum appeared in one of the series' most ambitious episodes, "A Fish Called Selma," as Troy McClure's (Phil Hartman) agent, MacArthur Parker. Elizabeth Taylor had one of the series' briefest but most well-known cameos, providing Maggie's voice when she said her first word, "Daddy," at the end of the episode "Lisa's First Word."

Several major guest appearances are still fondly remembered by fans of "The Simpsons," but for a show with so much history, it's easy to forget some of the big names that have appeared. And sometimes, fans might remember the characters without realizing they were voiced by guest stars.

Homer's (Dan Castellaneta) mom has only appeared on a handful of episodes of "The Simpsons," but she has become an important member of the Simpsons family, whom fans have taken into their hearts. What many viewers might not have realized, though, is that the character was voiced by none other than Hollywood legend Glenn Close.

Known for playing two villains you should never leave alone with your pets, as Alex Forrest in "Fatal Attraction" and Cruella de Vil in "101 Dalmatians," Close made quite the pivot to play Homer's loving, if reluctantly absent, mother. No stranger to an easily-missed guest appearance, Close also cameoed in the Peter Pan movie "Hook," where she was hidden behind a false beard to play a pirate in Captain Hook's (Dustin Hoffman) crew. In more recent years, Close picked up an Oscar nomination for her role in "The Wife," played Nova Prime in Marvel's "Guardians of the Galaxy," and appeared in the third "Knives Out" film, "Wake Up Dead Man."

Close first appeared as Mona on "The Simpsons" Season 7 episode "Mother Simpson," which revealed she had been on the run from the police since her radical activism in the 1960s. The episode's ending, which saw her parting from Homer once again, is one of the saddest moments in "Simpsons" history. Close's third appearance on the series, in "Mona Leaves-a," featured Mona's death, though she has returned in flashbacks, dreams, and a hallucination.

Another guest star on "The Simpsons" who might have flown under many fans' radars was John Goodman. Goodman appeared for a single episode, Season 11's "Take My Wife, Sleaze," playing Meathook, leader of the motorcycle gang Hell's Satans.

A star of the big screen as well as TV, Goodman's filmography is impressive. He has appeared in 2011 silent movie and Oscar darling "The Artist," played absolutely frightening villains in "Barton Fink" and "10 Cloverfield Lane," and portrayed a live-action Fred Flintstone in 1994's "The Flintstones." To a certain generation of fans, Goodman is best known as the voice of James P. "Sulley" Sullivan in the Disney Pixar classic "Monsters, Inc." Recently, he starred opposite Tom Cruise in Alejandro G. Iñárritu's "Digger." On TV, he has played roles including his major breakout role as Dan Conner in "Roseanne," Bill Randa on "Monarch: Legacy of Monsters," and air-conditioning-repair extraordinaire Vice Dean Laybourne on "Community."

The episode of "The Simpsons" which Goodman appeared saw Homer win a motorbike and start a local motorbike gang with Moe, Lenny, Carl, and Ned Flanders. Homer dubs the gang the Hell's Satans, earning the ire of another gang also called Hell's Satans. Goodman's Meathook leads this gang, who break into the Simpsons' house and take over. While there, they become enamored with Marge (Julie Kavner) as a maternal figure and positive influence, eventually kidnapping her. Homer wins Marge back in a fight with Meathook, where they use their bikes like swords.

Is there any voice quite as iconic as that of Darth Vader? James Earl Jones has lent his impressive timbre to "The Simpsons" on multiple occasions, most prevalently in the series' "Treehouse of Horror" Halloween specials.

To millions, Jones is of course the cybernetic Sith Lord Darth Vader from the Star Wars franchise. While the character was portrayed physically by the 6-foot-6-inch bodybuilder, David Prowse, Prowse's English West Country accent was far from the intimidating voice the character demanded. Enter Jones, who provided the voice uncredited in 1977's "Star Wars" and 1980's "The Empire Strikes Back," before finally being named as Darth Vader's voice in the credits of 1983's "Return of the Jedi." Outside of the Star Wars franchise, Jones famously voiced Mufasa, the father of Simba, in both the original and photorealistic CGI remake of Disney's "The Lion King."

Jones first appeared on "The Simpsons" in the series' first ever "Treehouse of Horror" special. Jones had a bit part as a removal man in the episode's first segment, then voiced the alien chef Serak the Preparer in the "Twilight Zone" parody segment "Hungry Are the Damned," and finally narrated the episode's adaptation of Edgar Allan Poe's "The Raven." Jones returned on "Treehouse of Horror V" for a brief cameo as an alternate universe's Maggie before his final "Simpsons" appearance narrating the episode "Das Bus."

"Lisa's Substitute" on Season 2 of "The Simpsons" saw Lisa Simpson (Yeardley Smith) finding an inspiring new role model in her substitute teacher Mr. Bergstrom, who taught her class at Springfield Elementary School while Miss Hoover (Maggie Roswell) was away with Lyme disease. Bergstrom only appeared in this one episode and while he made a lasting impact, it's easy to forget he was voiced by Hollywood megastar Dustin Hoffman.

Hoffman became a household name after his role in 1967's "The Graduate," in which he played Ben Braddock, a college graduate seduced by an older woman. Hoffman's subsequent credits included "All the President's Men," "Kramer vs. Kramer," "Tootsie" and "Rain Man." He has taken on more child-friendly roles in "Horton Hears a Who!," the Kung Fu Panda movies, and as the Captain Hook contending with Glenn Close's pirate in "Hook." Hoffman also appeared in HBO's "Luck," where he was directed by Michael Mann.

Hoffman's Mr. Bergstrom brought an unconventional teaching style to Lisa's classroom, helping the young Simpson family member rediscover a love for education and providing a stark contrast to her boorish father. When it came time for Mr. Bergstrom to leave Springfield Elementary, a tearful Lisa begged him not to leave. In a touching moment, Bergstrom left Lisa with a note to look back on whenever she felt lost or alone. It read: "You are Lisa Simpson."

One of the most psychedelic sequences to feature on "The Simpsons" saw Homer experiencing a strange, otherworldly hallucination after eating Guatemalan insanity peppers at Springfield's Annual Chilli Cook-Off on the episode "El Viaje Misterioso de Nuestro Jomer (The Mysterious Voyage of Homer)." In his hallucination, Homer met his spirit guide –- a talking coyote Homer dubbed "Space Coyote." The strange character is fondly remembered by "Simpsons" fans, but many might be surprised to learn he was voiced by Johnny Cash in one of the singer's several TV appearances.

Cash was a world-renowned singer-songwriter, primarily creating country, rockabilly and rock and roll music. Making his name in the 1950s and 1960s with songs like "I Walk the Line," "Ring of Fire," and "A Boy Named Sue," Cash led a long and successful career, producing hits until his death in 2003. His 2003 cover of "Hurt," originally by Nine Inch Nails, was a shocking direction for the singer, but his subdued, downbeat rendition has arguably become more well-known than the original.

On "The Simpsons," Cash's low and soothing voice imbued Homer's spirit guide with the gravitas required to carry dramatic weight. The Space Coyote set Homer on a quest to find his soulmate, sowing seeds of doubt as to whether it was Marge. When Homer and Marge finally reunited at the end of the episode, Homer proudly declared, "In your face, Space Coyote!"