'Abbott Elementary' Season 2: Our Favorite Teachers Are Back for Development Week in New Teaser (Exclusive)

Season 2 of the Emmy-nominated series premieres on Wednesday, Sept. 21.

Abbott Elementary is almost back on our screens, and ET is exclusively debuting the new teaser trailer for season 2 of ABC's hit new comedy series.

 After a highly acclaimed debut season, our favorite group of dedicated and passionate teachers is heading back to school for a new year and things get as chaotically adorable as we've come to expect.

In the new teaser, the teachers prepare for the upcoming school year with what creator Quinta Brunson's Janine calls the "calm before the storm," aka development week. Sheryl Lee Ralph's Barbara, Lisa Ann Walter's Melissa, Chris Perfetti's Jacob, Janelle James' Ava and Tyler James Williams' newly full-time Gregory are all in attendance as they ready the school -- and themselves -- for the kids' return.

Even Abbott’s eccentric custodian, Mr. Johnson (William Stanford Davis), who was promoted to series regular before production on season 2 began, gets into the new swing of things in the footage.

Of course, pandemonium returns when the kids make their appearance. Watch the teaser above.

Last month, the cast was joined at San Diego Comic-Con by executive producers Justin Halpern and Patrick Schumacker in a live virtual panel, where they first revealed the premiere date and that the upcoming season scored a rare full-season, 22-episode order

And while the cast remained tight-lipped on what other surprises are in store for season 2, especially when it comes to possible famous cameos, Brunson did offer one tease, "You're going to see a cameo in the first episode." 

"I'm not gonna tell you who it is but it's a really good one," she added, with Schumacker noting that they were only allowed the mysterious guest for "literally one day."  

"It's someone we didn't think we'd be able to get," Brunson teased. "It's one of the biggest stars in the world to me. They are the biggest star we've seen thus far at Abbott Elementary."

Fans will learn who the mystery star is when Abbott Elementary season 2 premieres on ABC, Wednesday, Sept. 21.