Katherine Marie Heigl (born November 24, 1978) is an American actress and producer, known for her role as Dr. Izzie Stevens on ABC's Grey's Anatomy.
Peter gets Lois a mask of Katherine to wear during sex in "Encyclopedia Griffin", pointing out that it can also be worn on the butt. He then proceeds to strap it to his nether regions and tells Lois that Katherine wants a French kiss.
Katherine Heigl is mentioned as the winner of the dog show in "Boy (Dog) Meets Girl (Dog)".