But CBS hit it out of the park with "Young Sheldon," which ... show's producers did manage to sneak Kaley Cuoco in during the series' third season for a stealthy cameo. Cuoco, of course, played ...

Before he joined the cast of Young Sheldon, Lance Barber played a completely different character on The Big Bang Theory.

American sitcom The Big Bang Theory centers around friends Leonard Hofstadter (Johnny Galecki), Sheldon Cooper (Jim Parsons), Penny Teller (Kaley Cuoco ... character titled Young Sheldon debuted ...