Dianna Agron and Cory Monteith were prohibited from attending rehearsals for the final "Lean on Me" number. The song moving Quinn and Finn are the actors' genuine emotional reactions.
First time the piano-guy is actually called by his name, Brad (which happens to be his real name).
This episode features Sarah Drew as Suzy Pepper who went on to be in Grey's Anatomy (2005) with Matthew Morrison (Will). Harry Shum, Jr (Mike Chang) joined the Grey's Anatomy cast in 2022.