Brian Thomas Smith. Plays Jack in Season 2 of Shrinking. Photo from Premiere Party

Brian Thomas Smith and Vince Vaughn in Bad Monkey.

Kaley Cuoco, Johnny Galecki, Simon Helberg, Jim Parsons, Brian Thomas Smith, and Kunal Nayyar in The Big Bang Theory (2007)

Brian Thomas Smith in The Big Bang Theory (2007)

Zack Johnson (Brian Thomas Smith) and Marissa Johnson (Lindsay Kraft) discussing future pregnancy details with Leonard and Penny in The Big Bang Theory Season 12 Episode15.

Brian Thomas Smith as the overly-friendly Freddy on United States of Al

Kaley Cuoco, Johnny Galecki, and Brian Thomas Smith in The Big Bang Theory (2007)

Kaley Cuoco, Johnny Galecki, Simon Helberg, and Brian Thomas Smith in The Big Bang Theory (2007)

Kaley Cuoco and Brian Thomas Smith in The Big Bang Theory (2007)

Kaley Cuoco, Johnny Galecki, Brian Thomas Smith, and Kunal Nayyar in The Big Bang Theory (2007)

Alessandra Torresani, Brian Thomas Smith, and Kunal Nayyar in The Big Bang Theory (2007)

Mayim Bialik, Kaley Cuoco, Johnny Galecki, Simon Helberg, Brian Thomas Smith, and Kunal Nayyar in The Big Bang Theory (2007)

John Ross Bowie, Kevin Sussman, Jim Parsons, and Brian Thomas Smith in The Big Bang Theory (2007)

John Ross Bowie, Kevin Sussman, and Brian Thomas Smith in The Big Bang Theory (2007)

John Ross Bowie, Jim Parsons, and Brian Thomas Smith in The Big Bang Theory (2007)

Brian Thomas Smith as Dougie in the film Hollywood Adventures.

Brian Thomas Smith on set with Dawei Tong and Xiaoming Huang in the Chinese blockbuster movie Hollywood Adventures. BTS is huge in China. 

Brian Thomas Smith as the outrages character Bjorn Hansen in the Fox Digital Studios series Suit Up. 

Brian Thomas Smith as Karl taking back what's his in the movie Concrete Blonde

Brian Thomas Smith as Karl in the movie Concrete Blondes.

Brian Thomas Smith on the run in a clever Direct TV commercial

Brian Thomas Smith as Phil Shifley in the award winning Direct TV campaign. 

Brian Thomas Smith guest stars as Zack on the Big Bang Theory season 3 finale.