In addition to returning stars including Billy Crystal, John Goodman, and Steve Buscemi, some new names are being announced for Pixar’s highly anticipated Monsters, Inc. prequel, Monsters University.

New voices who will join in on the fun this time around include geek god Nathan Fillion (Firefly, Slither), Bonnie Hunt (Jerry Maguire, The Green Mile), and John Krasinski (The Office, Away We Go).

Fillion will voice Johnny Worthington (seen above with the horns), the president of the Roar Omega Roar fraternity, while Krasinski will be a super star scarer at Monsters, Inc. and Hunt will voice a young Mike Wazowski’s grade school teacher.

All three have experience as voice actors, but Hunt is the only Pixar vet of the trio. She voiced characters in Cars and Cars 2, Toy Story 3, A Bug’s Life, and even Monsters, Inc., though it was a completely different character. Krasinski voiced characters in DreamWorks’ Shrek the Third and Monsters vs. Aliens. Fillion has voiced the Green Lantern in Green Lantern: Emerald Knights and Justice League: Doom, as well as characters in video games Halo 3, Halo: ODST, and Halo: Reach and animated shows like The Venture Brothers, American Dad!, and Robot Chicken.

The actors join some previously announced newcomers, such as Helen Mirren (The Queen), who will play Dean Hardscrabble; Alfred Molina (Spider-Man 2), who plays Professor Knight; Aubrey Plaza (Safety Not Guaranteed) in the role of Claire Wheeler); Tyler Labine (Tucker & Dale vs. Evil) as Brock Pearson); Dave Foley (NewsRadio) and Sean Hayes (Will & Grace), who voice Terry and Terri Perry; Charlie Day (It’s Always Sunny in Philadelphia) as Art; Joel Murray (God Bless America) as Don Carlton; and Pixar animator Peter Sohn (Ratatouille), who voices Scott “Squishy” Squibbles.

Be sure to head to Entertainment Weekly for images and descriptions of all of the characters!