A guest spot on a television sitcom, especially one as insanely popular as "The Big Bang Theory," is basically television law. There's no legally binding mandate, per se, but it would get pretty monotonous if every week followed our series leads with absolutely no one else showing up for a laugh or surprise jolt from the live studio audience. Given the show's primary focus on "geek culture," or rather a heavily commercialized version of such, it makes sense that nerdom heavy hitters like James Earl Jones, Mark Hamill, and Adam West would make an appearance throughout its 12-season run. But then you can't sustain a roster of guest spots without expanding your star power horizons.

The series' 11th and penultimate season saw folks like Kathy Bates, Peter MacNicol, and Jerry O'Connell pop in for a quick hello, but you may be surprised to learn that "Fallout" star Walton Goggins and his beautiful scruff did too.