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.
Physicists at Caltech, Leonard Hofstadter and Sheldon Cooper, live normally near their two equally geeky and social awkward friends. However, their lives change when a waitress moves into the flat next to them.
