"Abbott Elementary" returns to class with FXX's "It's Always Sunny in Philadelphia" gang in a highly anticipated crossover, premiering January 8 on ABC.

"Abbott Elementary" returns to class with the highly anticipated crossover episode with FXX's "It's Always Sunny in Philadelphia" on January 8.

ABC recently released a new promo for the episode, which is titled "Volunteers," with the following description:

"Ava announces the school district is sending a group of volunteers to help out at Abbott; however, when they arrive, things don't go as planned."

The promo hints at some hilarious, chaotic antics as the "It's Always Sunny" gang takes a field trip to Abbott Elementary.

"Welcome to Abbott Elementary- best elementary school in the universe," Janine (Quinta Brunson) says as she greets the "It's Always Sunny" crew. "Is that what this is?" responds Dee (Kaitlin Olson).

Mac (Rob McElhenney) tries to strike up a flirtatious conversation with Principal Ava (Janelle James). "Let me know if there's anything you need, and I mean anything," he says.

"You're trash, you know that!" janitor Mr. Johnson (William Stanford Davis) tells Frank (Danny DeVito), who responds "Coming from the sheriff of trash!"

On The Red Carpet spoke with Lisa Ann Walter in an exclusive about the filming of the episode, where she told us "As opposed to our normal 'Abbott' episode, it's unhinged. Those guys do not follow rules! I'm like 'Okay. We have no rules today?! Duck suit is on! Consider the challenge taken, Charlie Day!'"

Hilarity ensues in the can't-miss "Abbott Elementary" and "It's Always Sunny in Philadelphia" crossover event, premiering Wednesday, January 8th at 8:30 p.m. EST on ABC and streaming the next day on Hulu.