Jonathan Groff, Samuel, Damian Mcginty Jonathan Groff, Samuel, Damian Mcginty

Watch out, New Directions: Jesse St. James is back!

Jonathan Groff will be returning to Glee as the former Vocal Adrenaline rival and one-time New Directions co-coach. This time, however, he'll go back to being the competition. At Wednesday's celebration for the 300th musical number — a soulful, booty-shakin' mashup of Adele's "Rumor Has It" and "Someone Like You" — series boss Ryan Murphy revealed that Groff's Jesse St. James would be returning as the new coach of Vocal Adrenaline.

A note about the mashup: It looked as though the kids performing it were members of McKinley's other glee club, led by Shelby (Idina Menzel). The all-girl choir includes Mercedes, Sugar Motta... and two other familiar faces.

Check out our Glee spoilerpalooza!

But back to Groff! Murphy said the Broadway babe will have "many scenes" with The Glee Project's Alex Newell. "He's going to be the love child of Kurt and Mercedes and will turn to them for much advice," Murphy said. Over the summer, Newell won a (sweet) consolation prize — a two-episode role on Glee -- alongside Lindsay Pearce, last seen scaring the bejesus out of Rachel in the season premiere. She'll return in Episode 8 as "the Rachel of her school," Murphy said. "She will be competing against our groups."

As for Glee Project winner Damian McGinty, who arrives in Tuesday's episode, he says it'll be a bumpy road ahead for his character, Irish lad Roy Flannigan. "He comes in and he's having a really tough time fitting in and getting bullied a lot. He's very young," McGinty said. Fellow Glee Project winner Samuel Larsen will turn up in Episode 10 or 11 at the start of the new semester, according to Murphy, who previously teased that Larsen may come on as a relative of Puck (Mark Salling).

What are you most looking forward to seeing? Are you excited to check out what looks like Shelby's girl group?

Glee returns on Tuesday at 8/7c on Fox.