However, no TV cameo will be quite as treasured as his time on The Simpsons, most notably "They Saved Lisa's Brain". The episode sees Lisa invited into Springfield's local Mensa chapter, only for the group to grow power hungry and take control of the town, attempting to impose the rule of the smartest.
It's Hawking who saves the day, becoming one of Lisa's many mentors with the line: “I don’t know what is a bigger disappointment, my failure to formulate a unified field theory … or you.” He's also seen to be intrigued by Homer's theory of a "donut-shaped universe" and confesses he may steal it - a reference to actual theories that the universe may be toroidal in shape.
He went on to make three more appearances on the show, one he called "the best thing on American television". Hawking himself become enough of a popular Simpsons character that he received his very own action figure, complete with the boxing glove that erupts out of his chair to reprimand Homer when he imitates Hawking in an attempt to get him to pay a bar tab.