WATCH: Surprise Guest Joins Reneé Rapp On Stage During SNL Debut

Reneé Rapp made her SNL debut on Saturday (January 20) and just when we thought the show couldn't get any better, a surprise guests strutted onto the stage. The Mean Girls standout was joined by the original mean girl, Rachel McAdams (a.k.a. Regina George) who introduced her to the crowd. McAdams showed up and showed out in a bold, red fit as she passed the baton to Rapp who was cast as Regina George in the latest Mean Girls, released on January 12.

After the surprise introduction, Rapp delivered a star-studded performance of "Not My Fault" and was joined by yet another special guest. As if a surprise appearance from the iconic Rachel McAdams wasn't enough, hot girl Megan Thee Stallion shocked the audience by stepping out of a giant, revolving cake on stage in the middle of the song. The two turned up the heat, taking control of the venue in dynamic fits that left the audience starstruck and "like in love" with them. Rapp also performed 2023 hit, "Snow Angel," the title track of her debut album.

The show began with a monologue from Jacob Elordi, followed by a hilarious sketch where Rapp, Elordi, and Fire Island actor Bowen Yang pretended to be professional lip readers who dissected real-life pop culture moments that took place this year. Rapp released her first album, Snow Angel, in August 2023 and kicked off 2024 with the release of "Not My Fault," "Meet The Plastics," "World Burn," and "Someone Gets Hurt," all featured in the new Mean Girls film.

Rapp is set to kick off her "Snow Hard Feelings" world tour in Paris, France on February 13.