Gustin was introduced on "The First Time," an episode that tackled many "firsts" in the lives of McKinley High students Blaine Anderson (Darren Criss), Kurt Hummel (Chris Colfer), Rachel Berry (Lea Michele) and Finn Hudson (Cory Monteith). The students also put up their first big musical, the Leonard Bernstein-Stephen Sondheim-Arthur Laurents classic West Side Story.
On the Dalton Academy side, Gustin and Warblers performed a cover of Billy Joel's "Uptown Girl." Here, the new "Glee" student offers a behind-the-scenes look at filming the number and talks about his character, who is trying to interfere in Blaine's relationship with Kurt.
"Glee" airs Tuesday nights on Fox at 8 PM ET.
To watch the behind-the-scenes action with Gustin, look below: