Longtime Saturday Night Live cast member Kenan Thompson recently revealed how Robin Williams was cast for a near-silent cameo during a classic sketch. During the 1970s, the Dead Poets Society star began his career in San Francisco, performing stand-up comedy and honing his legendary improvisational skills. His talents landed him a lead role on the television comedy series Mork & Mindy before moving on to theatrical hits including Good Morning Vietnam, The World According to Garp, and Good Will Hunting among many others.
https://screenrant.com/saturday-night-live-robin-williams-cameo-explained/