Before Ken Jeong gave The Hangover wolf pack a cocaine mountain of troubles, and before he was delivering the result of Katherine Heigl and Seth Rogen's one-night stand in Knocked Up, he was actually giving out real medical help as a physician. In fact, he's still licensed to practice medicine in California!
Jeong isn't the only actor to land a breakout role out of sheer luck and good timing. Check out our gallery of 10 actors who were plucked from obscurity:
The Hangover 3 hits theaters May 23.