Former "Glee" star Chord Overstreet is set to guest star in the third season of the hit ABC comedy "The Middle."

The singing heartthrob will appear on a single episode as Ralph Wilkerson, the eccentric fourth grade teacher of Brick (Atticus Shaffer), whose unconventional educational style irks Brick's parents, played by Patricia Heaton and Neil Flynn.

The comedy also stars Charlie McDermott and Eden Sher.

Season three debuts September 21 with a one-hour season premiere, featuring guest (and Heaton's "Everybody Loves Raymond" co-star) Ray Romano.

Overstreet's episode will air the following week. "The Middle" airs on ABC Wednesdays at 8 pm/7 pm CT.

Overstreet played Sam Evans on FOX's "Glee," until deciding not to re-up for the show's third season. He recently appeared in "Glee: The 3D Concert Movie" and he'll soon be seen in "A Warrior's Heart."