Kenan Thompson learned a "wealth of career knowledge" when Chris Farley guest-starred on All That
https://people.com/tv/kenan-thompson-reflects-on-working-with-chris-farley-what-he-learned-from-him/
"It was one of the greatest days I've ever seen," Thompson says of Farley's guest appearance as The Chicago Ketchup Chef on a 1997 episode of the Nickelodeon sketch series. "I learned literally a wealth of career knowledge in three hours, just watching a pro take direction. But also, do what he wanted. It was amazing."