The founder of Microsoft makes his debut on the Emmy-winning sitcom The Big Bang Theory, reports Entertainment Weekly, the latest in a series of cameos by icons in the science and technology worlds.

Gates is making the pop culture rounds lately. He showed up Wednesday on the The Ellen DeGeneres Show and ended up discussing two of his most extravagant purchases since becoming a billionaire—a Porsche and a private plane—and failing a quiz on the price of groceries.

The Big Bang Theory has been adept at luring big names in business (who also happen to be geek icons) to the show, including Steve Wozniak, Stan Lee, and even Apple’s Siri.

The appearances are part of Gates’ effort to raise awareness about the work he and his wife Melinda are doing with the Bill & Melinda Gates Foundation—and show how people who aren’t billionaires can help with the group’s efforts.