may have won our hearts as the very smart (and very blond) Dr. Izzie Stevens on Grey's Anatomy
, but the actress has since experiment with strawberry blond, rich auburn and now a bold espresso shade. “At her request, I took Katherine a deep rich chocolate brown. It's the darkest she’s ever been, and she loves it," said her colorist Kim Vo
. Try on Katherine Heigl's many hairstyles now!