Hundreds of celebrities have voiced themselves on The Simpsons. But only the very best created highly memorable moments that stand out in the show's storied history. 

Here's the list of the 5 best celebrity cameos on The Simpsons:

5. Ringo Starr (season 2, 1991)

The legendary Beatles drummer was one of the first A-list names to appear in the animated sitcom in the early 1990s. Ringo lent his voice to the season 2 episode "Brush with Greatness" in 1991.

Ringo Starr in his guest cameo on The Simpsons, season 2, "Brush with Greatness."

"Brush with Greatness" sees Marge pursue her talent for painting. In the episode, it is revealed that Marge is a huge Beatles fan, and that she once sent a painting to her crush, Ringo Starr.

Ringo appears as himself in the episode. He sends Marge a letter after seeing her painting many years later in his endless supply of fan mail.

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4. Leonard Nimoy (season 4, 1993)

Star Trek actor Leonard Nimoy features as a guest passenger for the opening of the Springfield Monorail in the episode "Marge Vs. The Monorail." Several Star Trek references are made in the episode. Springfield's Mayor Quimby also mistakes Nimoy for a Star Wars actor.

Nimoy would also later reappear in the season 8 episode "The Springfield Files."

3. Tom Jones (season 4, 1992)

In "Marge Gets a Job," Marge joins Homer as an employee at the Springfield Nuclear Power Plant. She attracts the attention of Mr. Burns, who romantically pursues her.

Singer Tom Jones makes multiple appearances in the episode as a hostage of Mr. Burns. Burns attempts to woo Marge with private performances by the "It's Not Unusual" singer.

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2. Adam West (season 4, 1992)

The original "Batman" himself Adam West guested in the episode "Mr. Plow," from season 4. Homer and the family visit a car show in Springfield, where West attends alongside his famous "Batmobile."

The Simpson family's encounter with West quickly turns odd when the actor reminisces about his days in the campy '60s Batman series.

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1. George Harrison (season 5, 1993)

Beatle George Harrison makes one of the show's most popular cameos in the classic episode "Homer's Barbershop Quartet" - itself a music parody with many references to the Beatles. 

In the episode, Homer forms a barbershop quartet with Apu, Principal Skinner, and Barney Gumble. Their success takes them to the Grammys, where Homer meets George Harrison. The pair's encounter - which Homer calls "the greatest thrill of my life" - is one of TV's all-time great cameo moments.