The Many Famous Faces to Guest Star on Monk

For 8 seasons, audiences watched former homicide detective Adrian Monk (Tony Shalhoub) solve crimes on Monk despite struggles with obsessive-compulsive disorder. The show ran from 2002 to 2009 and throughout the series, Monk was accompanied by a group of friends who helped him through it all. While watching the small but mighty team worked case after case, you likely saw some awfully familiar faces coming and going in various storylines. Some of these guest stars were already big names before appearing on the series, while others appeared on Monk on their way to becoming household names.

Will any of the original series’ guest stars join the upcoming Mr. Monk’s Last Case: A Monk Movie, debuting on Peacock on Dec. 8? Maybe.

RELATED: Case Closed: Here's Where Monk and His Friends Left Off Ahead of the Reunion Movie

In the meantime, let’s take a look back at some of the biggest guest stars that joined the Monk cast over its original eight-year run and relive some priceless memories only Monk can create. 

Jeffrey Donovan as Steve Wagner

Jeffrey Donovan visits Build to discuss "Shut Eye" at Build Studio on November 27, 2017 in New York City. Photo: Dia Dipasupil/Getty Images

In 2006, during Monk Season 4, Episode 14, Donovan played Steve Wagner, an astronaut Monk suspects of killed someone. The episode, titled “Mr. Monk and the Astronaut” Sees Monk do everything he can to try to prove Donovan's character is indeed a killer despite limited evidence. No spoilers as to whether the man who would go on to helm shows like Burn Notice and Law & Order committed the grisly crime, bur as Monk fans know, he always solves the case somehow.

Melora Hardin as Monk's wife, Trudy

Melora Hardin attends an LA premiere event at Regal LA Live on September 13, 2019 in Los Angeles, California.

Hardin, known for her roles on The Office and The Bold Type (among others), actually had a very important role over her 10 episodes on Monk. Hardin played Monk’s wife, Trudy, who died as a result of a remote detonation of a car bomb that Monk previously believed was meant for him. Monk spent the series searching for additional clues and information related to her death. Hardin was the face of Monk's greatest mystery as well as his reason for everything he does, including some of his more debilitating compulsions. Losing her was a devastating blow but solving her murder gave him purpose. 

Laurie Metcalf as Cora Little

Laurie Metcalf attends the 73rd Annual Tony Awards at Radio City Music Hall on June 09, 2019 in New York City. Photo: Dimitrios Kambouris/Getty Images

Metcalf guest-starred in the episode for which Shalhoub later won an Emmy titled “Mr. Monk Bumps His Head." In the episode, Metcalf plays a woman named Cora Little who is unable to win over the detective because of his deep and enduring love for Trudy. Metcalf was also nominated for an Emmy for her performance in this episode, making it a can't-miss for all the Monk fans out there. 

John Turturro as Monk's brother, Ambrose

Tony Shalhoub as Adrian Monk and John Turturro as Ambrose Monk in an episode of Monk. Photo: USA Network

Turturro guest-starred in a handful of episodes over the years as Monk’s older brother, Ambrose. He first appears in Season 2, Episode 11, in which audiences found out that he’s agoraphobic. Ambrose calls with a tip for one of the cases that Monk is working on, but the situation is complicated since the two are estranged after Ambrose never contacted Monk following Trudy’s death. Monk investigates the tip and eventually solves the case but not before needing to go rescue his brother, who finds himself in similar danger. The experience reconnects the two siblings, opening the door for Turturro to appear again in the series and play a key role in finding Trudy's killer. 

Stanley Tucci as David Ruskin

Stanley Tucci attends the Cheltenham Literature Festival on October 7, 2022 in Cheltenham, England. Photo: David Levenson/Getty Images

Tucci appeared in an episode of Monk due to his long-standing friendship with Shalhoub, according to TV Guide. In the episode, Tucci plays a method actor hired to play Monk in a movie about his work. While working on his character, the actor eventually begins to buy in too much and starts to believe that he is in fact, Monk.

Niecy Nash as Varla Davis

Niecy Nash speaks onstage during the Fourth Annual Celebration of Black Cinema & Television, presented by the Critics Choice Association at Fairmont Century Plaza on December 06, 2021 in Los Angeles, California. Photo: Leon Bennett/Getty Images

Nash joined the cast for one episode in Season 3 called “Mr. Monk and the Girl Who Cried Wolf.” In th episode, Nash played a nurse temporarily replacing Monk’s nurse and assistant when she took a leave of absence to focus on a creative writing course.

Hector Elizondo as Neven Bell

Hector Elizondo attends the L.A. Theatre Works 40th Anniversary Gala at The Beverly Hilton Hotel on March 25, 2015 in Beverly Hills, California. Photo: Paul Archuleta/FilmMagic

Elizondo’s prolific career means he was already well-known before appearing on Monk. Elizondo joined the cast in Season 7, appearing in a number of episodes as Dr. Neven Bell, Monk’s analyst. There’s good news for Dr. Neven Bell fans. Elizondo is slated to return to the cast for Mr. Monk’s Last Case: A Monk Movie. 

Catch up on these performances and more before the movie hits Peacock in December. All eight seasons of Monk are now streaming on Peacock.