Johnny Galecki is a Belgian-born American actor, best known for his roles as David Healy in Roseanne, Rusty Griswold in National Lampoon's Christmas Vacation, and as Leonard Hofstadter in The Big Bang Theory.
Luke Gardner, who is a third child in a world where only two children are allowed per family. He lives in hiding and befriends a neighboring third child, Jen Talbot.
