‘IT: Welcome to Derry’ episode 3: Did you spot the Andy Muschietti cameo?

Who does Andy Muschietti play in IT: Welcome to Derry episode 3?
Episode 3 starts with a trip back to 1908, where a young boy visits a dusty funfair that comes complete with a “Human Freaks” sideshow. As he walks inside through a hall of mirrors, we hear the jangling sound of piano keys.
A man playing said piano appears with cigarette dangling from his mouth and turns his head to bark a gruff “keep moving!” at the boy, followed by a slightly sinister laugh. This piano player is none other than Andy Muschietti himself.
It’s a brief, but fun, appearance, adding nicely to the discordantly creepy sequence which ends with the boy running screaming from the tent after a man with one eye jumps out of the shadows to scare him.
This isn’t the first cameo Andy Muschietti has had in the IT universe, either. In IT: Chapter Two, he also pops up as a customer in the pharmacy during a scene with Eddie Kaspbrak (Eddie Ransome).