TV's biggest comedy The Big Bang Theory is getting a spin-off this fall with Young Sheldon, a prequel about Sheldon Cooper's childhood.

Iain Armitage stars as the titular boy genius (grown-up Sheldon Jim Parsons will be providing voiceover narration), who is a misfit growing up in the bible-thumping backwater (fictional) East Texas town of Medford. The series starts in 1989 and follows him as a begins high school at age 9. Intellectually, he's perhaps overqualified for 9th grade, but socially he's completely incompetent. High school is hard for everyone, but it's going to be even harder for a rules-loving nine-year-old who knows he's smarter than everyone around him and says whatever he's thinking.

Things aren't easy at home, either. Though his mother Mary (Zoe Perry) works really hard to be his advocate, protector and translator, even she doesn't totally know what to do with him, especially regarding his disregard for religion. His father George (Lance Barber) is a jock who looks at his son like he's an alien. And Sheldon doesn't get along with his older brother George Jr. (Montana Jordan) and his twin sister Missy (Raegan Revord) at all, especially now that he's in the same grade as George.

Unlike The Big Bang Theory, Young Sheldon is be a single-camera, laugh track-free sitcom. It's created by Big Bang's co-creator Chuck Lorre and showrunner Steve Molaro. They brought in a ringer to direct the pilot — Iron Man's Jon Favreau, who also gets an executive producer credit. Jim Parsons is also an executive producer with his partner in production and love Todd Spiewak.

Fun fact: Zoe Perry is the real-life daughter of Laurie Metcalf, who plays Mary Cooper on The Big Bang Theory.

On the business side, CBS executives told reporters during a call earlier this week that they don't expect it to be as big as The Big Bang Theory, but are confident that the show can find an audience beyond just Big Bang Theory fans.

One thing we don't know is if we're going to see the origin of "bazinga." Sheldon stopped saying this catchphrase on The Big Bang Theory years ago, but maybe it'll come back for a full circle moment.

Young Sheldon will premiere with a special preview on Monday, September 25 at 8:30/7:30c before moving to its regular time Thursdays at 8:30/7:30c after The Big Bang Theory on November 2.