Question: Who was the director of the flim in which an American actor, known for playing Stuart Bloom on the CBS sitcom "The Big Bang Theory", was a star??

Context paragraphs:
The Big Bang Theory (season 1): The first season of the American sitcom "The Big Bang Theory" was originally aired on CBS from September 24, 2007, to May 19, 2008, over 17 episodes.  An unaired pilot also exists.  The Season 1 DVD came without a gag reel and is, so far, the only "Big Bang Theory" DVD set not to have one.  The reissued Blu-ray, was released July 10, 2012, and includes a gag reel that is exclusive to the set.  The episodes on Blu-ray are all in remastered surround sound, whereas the DVD version had stereo.  Two of the main cast, Sheldon and Leonard, are named after actor, director, and producer Sheldon Leonard.

Insanitarium: Insanitarium is a 2008 American direct-to-video horror-thriller film starring Jesse Metcalfe, Kiele Sanchez, Kevin Sussman, Olivia Munn, Carla Gallo and Peter Stormare.  The film is directed by Jeff Buhler.

Kevin Sussman: Kevin Sussman (born December 4, 1970) is an American actor.  He is known for playing Stuart Bloom on the CBS sitcom "The Big Bang Theory" and Walter on the ABC comedy-drama "Ugly Betty".  Starting with the sixth season of "The Big Bang Theory", he was promoted to a series regular.

Johnny Galecki: John Mark Galecki (born April 30, 1975) is an American actor.  He is known for playing David Healy in the ABC sitcom "Roseanne" from 1992 to 1997 and Dr. Leonard Hofstadter in the CBS sitcom "The Big Bang Theory" since 2007.  Galecki also appeared in the films "National Lampoon's Christmas Vacation" (1989), "Prancer" (1989), "Suicide Kings" (1997), "I Know What You Did Last Summer" (1997), "Bookies" (2003), and "In Time" (2011).

Sheldon Cooper: Sheldon Lee Cooper, Ph.D., Sc.D. , is a fictional character in the CBS television series "The Big Bang Theory" and "Young Sheldon", portrayed by actor Jim Parsons in "The Big Bang Theory" and Iain Armitage in "Young Sheldon".  For his portrayal, Parsons has won four Primetime Emmy Awards, a Golden Globe Award, a TCA Award, and two Critics' Choice Television Awards.  The childhood of the character is the focus of "Young Sheldon", the show being set in 1989, when 9-year-old Sheldon, who has skipped ahead four grades, starts high school alongside his older brother.

The Big Bang Theory (season 8): The eighth season of the American sitcom "The Big Bang Theory" first aired on CBS with a one-hour premiere on Monday, September 22, 2014.  It returned to its previous Thursday time slot on October 30 for the season's seventh episode.  It concluded on May 7, 2015.  On March 12, 2014, "The Big Bang Theory" was renewed for an additional three years, extending it through the 2016–17 season for a total of ten seasons.

Young Sheldon: Young Sheldon (stylized as young Sheldon) is an American television sitcom on CBS created by Chuck Lorre and Steven Molaro.  The series is a spin-off prequel to "The Big Bang Theory" and follows the character Sheldon Cooper at the age of 9, living with his family in East Texas and going to high school.  Iain Armitage stars as young Sheldon, alongside Zoe Perry, Lance Barber, Montana Jordan, and Raegan Revord.  Jim Parsons, who portrays an adult Sheldon Cooper on "The Big Bang Theory", narrates the series and serves as an executive producer.

Jim Parsons: James Joseph Parsons (born March 24, 1973) is an American actor.  He is known for playing Sheldon Cooper in the CBS sitcom "The Big Bang Theory".  He has received several awards for his performance, including four Primetime Emmy Awards for Outstanding Lead Actor in a Comedy Series and the Golden Globe Award for Best Actor in a Television Series Musical or Comedy.

Religious interpretations of the Big Bang theory: Since the emergence of the Big Bang theory as the dominant physical cosmological paradigm, there have been a variety of reactions by religious groups regarding its implications for religious cosmologies.  Some accept the scientific evidence at face value, some seek to harmonize the Big Bang with their religious tenets, and some reject or ignore the evidence for the Big Bang theory.

The Big Bang Theory (season 9): The ninth season of the American sitcom "The Big Bang Theory" started airing on CBS on Monday, September 21, 2015.  It returned to its regular Thursday time slot on November 5, 2015 for the season's seventh episode.  It concluded on May 12, 2016.  On March 12, 2014, "The Big Bang Theory" was renewed for an additional three years, extending it through the 2016–17 season for a total of ten seasons.  Laura Spencer was upgraded to the main cast during the season as Dr. Emily Sweeney, after being a recurring cast member for two seasons.

Supporting paragraphs: Insanitarium Kevin Sussman
Answer: Jeff Buhler