Criss acted opposite The Flash star Grant Gustin when Gustin played the openly gay and slightly villainous Warbler Sebastian in Season 3.
He then shared the stage with Supergirl leading lady Melissa Benoist when she joined Glee as the shy Marley Rose in Season 4.
He joined the show in its second season and stuck around all the way to the sixth and final season.
Both were members of the StarKid Productions theater group, which produced original musicals like A Very Potter Musical, Me and My Dick, and Holy Musical [email protected]!