Netflix's Cobra Kai Season 4: What to Know About That Cameo

This article contains spoilers for episode 9 of Cobra Kai season 4.

Who knew the fight for the soul of the Valley could bring in such star power?!

At the beginning of Cobra Kai season 4's penultimate episode on Netflix, all the local dojos — including Miyagi Do, led by Daniel LaRusso (Ralph Macchio); Eagle Fang, led by Johnny Lawrence (William Zabka); and Cobra Kai, led by John Kreese (Martin Kove) and Terry Silver (Thomas Ian Griffith) — have gathered for the 51st annual All-Valley Karate Championship. After a few opening rounds of skills competitions, the president of the organization that puts on the event grabs a microphone.

"Ladies and gentlemen, the male and female division qualifiers are about to begin, and with them, we enter a new era," he declares. "That's why we need a very special guest to kick things off. Let's give a big All-Valley welcome to multi-Grammy Award-winning international superstar Carrie Underwood!"

And jaws. hit. the. floor. Both on the show and, presumably, in your home. "Holy crap," Amanda LaRusso (Courtney Henggeler) shouts.

"Hello, All-Valley!" Underwood says. "I am so honored to be here. I didn't see a lot of karate growing up in Oklahoma, but, you guys know I love to compete, just like these wonderful young men and young women. One thing I have learned is that everyone gets their shot, their chance in the spotlight. Everyone gets their moment. This one's yours."

And then she proceeds to perform a cover of Survivor's "The Moment of Truth," which was on the original Karate Kid soundtrack.

While Netflix and show creators Josh Heald, Jon Hurwitz and Hayden Schlossberg have yet to comment on how such a special surprise came to fruition, we do know how it started.

"Just started watching #kobraKai on Netflix. Ummmm...it's kinda awesome!" Underwood tweeted in August 2020. She quickly followed that up with another tweet, correcting herself: "Guess I could've at least spelled it right. I promise I do know how to spell Cobra...I just legit thought that's the way it was spelled in the movie/show. I'll do better next time. #CobraKaiNeverDies."

Macchio was quick to reply, "Thanks for the shout! We love doing the show. Enjoy!!" And Zabka chimed in, "Amazing! Thank you @carrieunderwood welcome to the dojo."

But the show's social media wasn't about to show Underwood such mercy. "We believe you, Karrie," they responded.

When the country star replied, "I deserve this," the show officially welcomed her to the dojo.

According to Jacob Bertrand, who plays Hawk, Underwood's appearance was indeed "so shocking."

"The writers were trying to think of people that they could have on to do the concert for the All-Valley and remembered that she's a mega-fan of the show," Bertrand, 21, tells PEOPLE. "They offered it to her and she was like, 'Yes, of course I will. I would totally do it.' That was really sweet of her."

He and his costars learned that Underwood, 38, would be showing up just days before her appearance.

"We knew a couple of days before when we read the script, but other than that, it was a complete shock to everybody," he says. "The background [actors] had no idea and they were freaking out when she came on."

Bertrand adds, "And she fricking killed it on the day. My God, she was belting."

Off-camera, Underwood was just as impressive. "I got to talk to her for a little bit," Bertrand says. "She was the nicest lady ever."

Cobra Kai is streaming now on Netflix.