It's hard to believe it's been almost 16 years since "Friends" fans first set eyes on Ross and Rachel's adorable daughter, Emma.

Now, baby Emma — or rather the twins who played her, Noelle and Cali Sheldon — are teenagers and starring in Jordan Peele's terrifying new thriller, "Us."

Rachel (Jennifer Aniston) holds baby Emma (Cali Sheldon/Noelle Sheldon) as she chats with her sister Amy (guest star Christina Applegate) in this 2003 scene from "Friends." NBC

And this time around, the girls aren't acting so sweet.

While the worst thing little Emma ever did was shock her mom (played by Jennifer Aniston) with her love for Sir Mix-a-Lot's hit song "Baby Got Back," the 16-year-old Sheldon sisters play much nastier characters in "Us."

Noelle Sheldon (Lindsey Tyler) and Cali Sheldon (Becca Tyler) share a scene with co-star Shahadi Wright Joseph (Zora Wilson) in Jordan Peele's new thriller "Us." Universal Studios via Everett Collection

The twins star as Becca and Lindsey, the obnoxious daughters of Kitty Tyler (Elisabeth Moss) and her husband, Josh (Tim Heidecker).

They spend their on-screen time playing cruel pranks on others, but they also get to show off their impressive gymnastics skills.

"They have a couple of scenes where they really steal the show,” director Peele told Entertainment Tonight.

Peele even added a little Easter egg for sharp-eyed "Friends" fans: a tattoo of the twins on Josh’s forearm that was created from an image of them when they played baby Emma.

Even though a decade and a half has passed since Noelle and Cali were part of the "Friends" family, they obviously still have warm feelings for their one-time TV mom.

While preparing for the "Us" premiere last month, the two swung by the Hollywood Walk of Fame to pose by Aniston's star.

"We found the coolest star,” Noelle captioned a snap of the sweet moment.

"Us" is playing in theaters across the country right now.