Let's hope the Burn Book is made with Dunder Mifflin paper.

Jenna Fischer, who played Pam on all nine seasons of NBC's The Office, has joined the cast of Paramount+'s upcoming Mean Girls movie musical, E! News confirms.

The actress will take on the role of Ms. Heron—played by Ana Gasteyer in the 2004 movie—the mother of Cady Heron, who was played by Lindsay Lohan in the film.

Angourie Rice—best known for playing Betty Brant in 2019's Spider-Man: Far From Home and 2021's Spider-Man: No Way Home—will play Cady in the movie musical, which is based on the Broadway musical that premiered in October 2017.

Tina Fey, who wrote the 2004 movie and the Broadway adaptation, is pulling the Mean Girls trifecta as writer of the Paramount+ version, too. 

As for the other iconic roles?

Sex Lives of College Girls star Reneé Rapp, Moana's Auli'i Cravalho and Tony winner Jaquel Spivey will play Regina, Janis and Damian, respectively.

In the original film version, Rachel McAdams played Regina, Lizzy Caplan played Janis and Daniel Franzeze played Damian. 

The roles of Karen, Gretchen and Aaron—played by Amanda Seyfried, Lacey Chabert and Jonathan Bennett in the movie—have not yet been cast. 

During a Feb. 16 appearance on Late Night with Seth Meyers, Fey revealed that she and Tim Meadows would also appear in the new adaptation, reprising their movie roles as Ms. Norbury and principal Duvall, respectively.

In her conversation host Seth Meyers, Fey explained how the musical adaptation will differ from the stage show. 

"The songs are sounding more pop," she explained. "It's a fascinating process, because in Broadway, everything has to play to the back of the house and in movies you can come back in and things can play really intimately."

While we wait for the movie musical, the OG Mean Girls movie is available to stream on Paramount+.