Dianna Agron and Grant Gustin

Dianna Agron and Grant Gustin are the latest Glee stars set to mentor on The Glee Project, according to The Hollywood Reporter.

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Gustin, who portrays Warbler villain Sebastian, will appear in the July 17 episode, which features the theme "Theatricality." Meanwhile, Agron, who plays former Cheerio Quinn, will appear in the Aug. 7 episode which focuses on the new theme "Actability."

Other mentors this season include Chris Colfer, Amber Riley, Darren Criss, Jane Lynch, Lea Michele, Cory Monteith, Samuel Larsen, Kevin McHale and Naya Rivera.

The Glee Project airs Tuesdays at 10/9c on Oxygen.