Schitt's Creek alum Dan Levy is paying tribute to his onscreen mom, Catherine O'Hara, two months after her death. Levy, 42, was a guest on The Tonight Show Starring Jimmy Fallon on Tuesday, March 31, and took a moment to remember O'Hara after host Jimmy Fallon told him he was "so sorry about the passing" of the actress. "Listen, it's like a collective loss, I think," Levy said. "She was the greatest. She's irreplaceable. I think the great comfort for me has just been to see how loved she was. The outpouring ... everyone felt like they kind of knew her.