High School Musical: The Musical: The Series is getting a very special guest in Friday's episode: The original Ryan from the flagship film that inspired the series, Lucas Grabeel, will pay a visit to offer some last-minute inspiration to Miss Jenn (Kate Reinders) as the production threatens to fall apart after the Thanksgiving fire in the robotics lab.

While we can't reveal exactly how Grabeel finds his way into the story, which is centered on a theater department at the real East High that is trying to launch their own production of High School Musical, TV Guide did speak to the actor about returning to the world of High School Musical and he teased how he can help these kids — and specifically Miss Jenn — find their light on the stage.

"What's interesting is obviously I'm coming back as Lucas, and not Ryan, and I'm there to help Miss Jenn realize what is truly important. In a lot of ways that's very classic High School Musical storyline, that making it all about yourself or making it all about one thing, all about basketball or all about musicals, isn't always the right way to go," Grabeel told us. "Making it all about yourself is forgetting why she's doing this job. She's doing this because she loves kids, she loves educating them and instilling a passion in them that they can do anything. Harping on some old memory that isn't really a big deal anymore isn't worth their time. So this is the role of a lifetime, to help these kids become the best versions of themselves."

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The two will get to perform a number again, which can be seen in the sneak peek above. However, it's been almost a decade since Grabeel has been part of this world. Even if his return is in a different capacity than he's used to for this episode, that didn't stop the nostalgia from washing over him when he was on set. And yes, he did get to spend time with the next generation of High School Musical stars.

"It was great walking in, having that nostalgic feeling, meeting or seeing so many familiar faces and then meeting the cast was really surreal," he explained. "They're so incredibly talented, and so sweet, and nice and very welcoming to me... You know, they treated me like I was some king or celebrity or something. So that was unexpected and just really, they're just nice kids and they're so talented, that you don't see that very often."

Grabeel is the first of the core HSM crew to make an appearance on the show (KayCee Stroh, who had a small part in the first and third films, made a brief cameo in Episode 5). However, Grabeel is hoping that his appearance will encourage OG High School Musical fans to tune in and get invested in the series as a whole.

"The reason I said yes and the reason that I want people to watch it is because I'm hoping that by me doing this, it's kind of a stamp of approval from all of us from the old clan, that I believe in this. I trust in it and I really hope that it does really well," he explained. "I think it's the perfect way to continue on the legacy of High School Musical. I just was so excited and grateful to be a part of it that I hope that people get to share in that joy that I had in doing it."

Grabeel's episode of High School Musical: The Musical: The Series premieres Friday, Dec. 27 on Disney+. Find out what you can stream on the service here.

(Disclosure: TV Guide is owned by CBS Interactive, a division of ViacomCBS)

Lucas Grabeel and Kate Reinders, <em>High School Musical: The Musical: The Series</em>Lucas Grabeel and Kate Reinders, High School Musical: The Musical: The Series