The film, penned by Colfer, is directed by Brian Dannelly and centers on Colfer's character, a teenager who has been struck and killed by a bolt of lightning. A series of flashbacks then chronicle his exploits as he blackmails his classmates into contributing to a literary magazine he's publishing.
Janney has signed on to play Colfer's mother in the film. According to his Twitter account the "Glee" star says, "I couldn't be more thrilled!"
The pair will begin shooting July 11 in Los Angeles after Colfer finishes the "Glee Live! In Concert!" European Tour and before he begins production on the Fox show's third season.
David Permut produces alongside Rob Aguire and Evil Media Empire's Mia Chang. Colfer and his manager Glenn Rigberg are executive producers with Jason Michael Berman.
Janney was nominated for a Tony Award in 2009 for her performance in 9 to 5. She has also been seen on Broadway in A View From the Bridge and Present Laughter.
Colfer, who won the Golden Globe for his performance as Kurt Hummel in "Glee," has also penned a pilot that the Disney Channel will shoot, entitled "The Little Leftover Witch"; he will publish two books with Little, Brown Books for Young Readers that will be released in summer 2012.