Question: Customer Loyalty is an episode of The Office that guest stars which Greek-Canadian comedian?

full_context: Document 1: Christos Callow: Christos Callow was born in Athens in 1955. He studied vocal music at the National Conservatory in Athens and theatre at the Katselis Drama School. In 1979 he was given the part of Archbishop Ansnan in Jesus Christ Superstar. Callow appeared in numerous TV series including Granada Television's production of Lord Elgin and Some Stones of No Value. In 1990, he was selected to represent Greece at the Eurovision Song Contest in Zagreb with the song "Horis Skopo" (Without Purpose). The song was placed 19th out of 22 entries.
Document 2: Dino Stamatopoulos: Konstantinos "Dino" Stamatopoulos (born December 14, 1964) is an American writer, producer, and actor. He has worked on TV programs such as "Mr. Show", "TV Funhouse", "Mad TV", "The Dana Carvey Show", "Late Show with David Letterman", and "Late Night with Conan O'Brien". He has also created multiple animated TV shows such as "Moral Orel", "Mary Shelley's Frankenhole", and "High School USA!". As an actor, he is best known for his recurring role as the character Alex "Star-Burns" Osbourne on the NBC comedy series "Community", on which he also worked as a producer and consulting writer.
Document 3: The Office (U.S. season 9): The ninth and final season of the American television comedy "The Office" premiered on NBC on September 20, 2012, and concluded on May 16, 2013, consisting of 25 episodes. "The Office" is an American adaptation of the British comedy series of the same name, and is presented in a mockumentary format, portraying the daily lives of office employees in the Scranton, Pennsylvania branch of the fictitious Dunder Mifflin Paper Company. The ninth season of "The Office" aired on Thursdays at 9:00 p.m. (Eastern) in the United States, as part of the Comedy Night Done Right television block. This is the second season not to star Steve Carell as lead character Michael Scott, although he returned for a cameo appearance in the series finale.
Document 4: Louis Mandylor: Louis Mandylor (born Elias Theodosopoulos; Greek: Ηλίας Θεοδοσόπουλος; 13 September 1966) is a Greek Australian film and television actor. He is best recognized as Nick Portokalos in "My Big Fat Greek Wedding" (2002), a role he reprised in the sequel "My Big Fat Greek Wedding 2" (2016).
Document 5: Moving On (The Office): "Moving On" is the sixteenth episode of the ninth season of the American comedy television series "The Office" and the 192nd episode overall. The episode was written by Graham Wagner. It was directed by Jon Favreau. It originally aired on NBC on February 14, 2013. The episode guest stars Bob Odenkirk, Mary Gillis, Collette Wolfe, and Andy Buckley. The episode also features the return of former series regular Zach Woods as Gabe Lewis.
Document 6: Russell Peters: Russell Dominic Peters (born September 29, 1970) is a Canadian comedian and actor of Indian descent. He began performing in Toronto in 1989 and won a Gemini Award in 2008. He currently lives in Los Angeles.
Document 7: Shareholder Meeting: "Shareholder Meeting" is the 11th episode of the sixth season of the U.S. comedy series "The Office" and the show's 111th episode overall. It was written by Justin Spitzer and directed by Charles McDougall, and originally aired in the United States on NBC on November 19, 2009.
Document 8: Customer Loyalty (The Office): "Customer Loyalty" is the twelfth episode of the ninth season of the American comedy television series "The Office". The episode was written by Jonathan Green and Gabe Miller, and directed by Kelly Cantley. It originally aired on NBC on January 24, 2013. The episode guest stars Chris Diamantopoulos as Brian the boom mike operator, and Ben Silverman as Isaac, a coworker of Jim's.
Document 9: Chris Diamantopoulos: Christopher "Chris" Diamantopoulos (born May 9, 1975; Greek: Χριστόφορος "Κρις" Διαμαντόπουλος ) is a Greek-Canadian actor and comedian.
Document 10: Suit Warehouse: "Suit Warehouse" is the eleventh episode of the ninth season of the American comedy television series "The Office" and the 187th episode overall. The episode was written by Dan Greaney and directed by Matt Sohn. It originally aired on NBC on January 17, 2013.
Document 11: Jury Duty (The Office): "Jury Duty" is the thirteenth episode of the eighth season of the American comedy television series "The Office" and the show's 165th episode overall. The episode aired on NBC in the United States on February 2, 2012. The episode was written by Aaron Shure and directed by Eric Appel. The episode guest starred Jack Coleman, Lindsey Broad, and Mark Proksch.
Document 12: Chris Spheeris: Chris Spheeris (in Greek: Χρήστος Σφυρής) is a Greek-American composer of instrumental music. He is a producer, vocalist and multi-instrumentalist. Chris is the cousin of Penelope Spheeris and her brother Jimmie Spheeris. Born in Milwaukee, Wisconsin, Chris began writing songs on his guitar as a teenager. In 1985, Chris began composing for film. His work in collaboration with filmmaker Chip Duncan includes the television series Is Anyone Listening, the series Mystic Lands (Discovery Networks), In A Just World (PBS) and the classroom production entitled The Life & Death of Glaciers (Discovery Education).
Document 13: Chris Lilley (comedian): Christopher Daniel Lilley (born 1974–75) is an Australian comedian, television producer, actor, musician and writer. He is a two-time winner of the Logie Award for Most Popular Actor, he is known for his creation and portrayal of several characters in the mockumentary television series "" (2005), "Summer Heights High" (2007), "Angry Boys" (2011), "" (2013) and "Jonah from Tonga" (2014).
Document 14: Double Date (The Office): "Double Date" is the 9th episode of the sixth season of the U.S. comedy series "The Office" and the show's 109th episode overall. It was written by Charlie Grandy and directed by Seth Gordon. It originally aired on NBC on November 5, 2009.
Document 15: Chris Grismer: Chris Grismer is a Canadian director and producer of film, television and music videos, now residing in Los Angeles. His credits include "Killjoys", "The Vampire Diaries", "The Originals (TV series)", "The Nine Lives Of Chloe King", "Playmakers", "This Is Wonderland", "Queer As Folk", "Pretty Little Liars". As a music video director, he has directed videos for Arcade Fire, Broken Social Scene, Metric, Stars, Death From Above 1979, Magneta Lane, The Fembots and Motion City Soundtrack. He was nominated for a Gemini Award in 2009 for his work on "Being Erica".
ground_truth: Christopher "Chris" Diamantopoulos