Right now, it's very possible that Maroon 5 will perform their Cardi B-featuring, currently No. 2 hit "Girls Like You" at the Super Bowl halftime show in 2019. Reports last week pointed to the band as the show's featured performers — and now, there's a rumor about Cardi potentially even getting her own set during the show.

But that's still over four months away. In the meantime, Adam Levine and co. are out on the road touring behind Red Pill Blues, and at their stop in Nashville on September 23, they welcomed a very special guest to the stage (whose name is not Cardi B): none other than Millie Bobby Brown.

The 14-year-old Stranger Things star popped up right around Cardi's part to sub in for the rapper, handling the bars herself. She stuck around until the end of the song and even ran down the band's runway stage to connect with fans.

"soooo 2nite was insane!!!" she wrote on Instagram when she posted the clip. "i love @maroon5 and my dear friend @adamlevine."

There's some precedent here: MBB appeared dancing and lip-synching in the band's "Girls Like You" music video alongside cultural heavy-hitters like Gal Gadot, Tiffany Haddish, Aly Raisman, and so many others. Plus, Brown showed off her bars in the past, via a rapped Stranger Things recap on The Tonight Show last year.

No word yet on whether she'll make this a permanent thing or reprise her role at the Super Bowl next year. In the meantime, you can relive the action above, then check out both Cardi and Millie in action in the "Girls Like You" music video below.