'Mean Girls': See Reneé Rapp's Epic Reaction to Rachel McAdams Praising Her as 'Amazing' (Exclusive)

McAdams starred as Regina George in the 2004 film, a role that Rapp is taking on in the upcoming movie musical.

Reneé Rapp is thrilled to have Rachel McAdams' stamp of approval. ET's Denny Directo spoke with the cast of the upcoming Mean Girls movie musical, and delighted Rapp, who plays Regina George in the project, by sharing a video of McAdams, who originated the iconic character in the 2004 movie, praising her.

"I don't think she can do any wrong," McAdams previously told ET of Rapp taking on the part. "She is amazing. She's already got me beat with that voice. I'm just excited to see her incarnation. It's such a great character. It's so much fun to play. I hope she has a great time with it. I can't wait to see it."

Upon seeing McAdams' praise, Rapp gushed to ET, "She's so cool. She's so sick. I saw this and I was so geeked. I love her. I'm obsessed with her."

McAdams isn't the only original cast member to speak out about the actor taking on their part. Jaquel Spivey told ET that he's heard from Daniel Franzese, who played Damian in the original movie.

"Daniel reached out. He's very kind. He's very sweet," Spivey said. "I haven't met him in person yet, but he's been nothing but just the sweetest person. To have the torch passed, and just to let him know that I am honoring your work and I'm also creating Damian for myself, and to have that respected is really a beautiful thing."

For Angourie Rice, plays Cady Heron, the role originated by Lindsay Lohan, having Tina Fey involved in the movie musical was an unforgettable experience.

"One of the most special things for me was hearing Tina's memories from filming the 2004 movie," Rice told ET of Fey, who wrote the original film and the Broadway musical, and plays Ms. Norbury in both film adaptations. "[I was] sort of asking her about what that was like and then her telling us about it and how they didn't know what they were making at the time."

After its release, the 2004 film "blew up" and became iconic, which made taking on the role such a big deal for Rice.

"There's a lot of pressure, because there are so many fans of the 2004 movie and the musical and I am one of them. You don't want to let the fans down. You also don't want to let yourself down," she said. "It feels very important and it feels like a big responsibility, but it was something that I really wanted to do. Who says no to an opportunity like this to work with Tina Fey, to work with the music team, to work with the director? The fear didn't didn't overcome me enough to say no."

Meanwhile, Rapp, who previously played Regina George on Broadway, tried not to overthink everything the role and the movie mean.

"I try not to think too much into something. I try to just do it and do it how I feel like I'm gonna stay in that moment. The second I start to overthink, then I start to kind of be something that I'm authentically not," she said. "That's not what I wanted for this. That's also not where I'm at in my life at the moment."

"It's very different 'cause when I was doing it on Broadway I was 18, 19 and now I'm 23, 24, so I'm a different person," Rapp added. "... I also think like cinematic medium is more catered to the acting that I like to do. I like the intimacy and I like the nuance that you don't necessarily get on stage."

As for what fans can expect from the movie musical, Christopher Briney, who plays Aaron Samuels, teased that it's a mix of the original film, the Broadway musical and something totally new.

"It's sort of all of it. Story-wise it's similar. You sort of know where it's gonna go. It's not [a surprise], and you wouldn't, I don't think, want it to be," he said. "But the path it takes is so different and it takes influence from all these places and it pays homage in the way it should, but not too much. These characters live in their own universe and have their own lives."

Meanwhile, Avantika Vandanapu, who plays Karen in the movie, called the project "nostalgic, exhilarating, iconic."

"I think it really is just the perfect blend of the '04 movie and the musical for the die hard musical fans," Bebe Wood, the new Gretchen Wieners, agreed to ET. "On top of that, we're all kind of doing our own thing as well, so I think it is kind of the perfect mix of everything you know and love whilst also has a bit of a spin on it."

Auli'i Cravalho, who plays Janis, concurred, telling ET, "It really feels like an honor to take on the characters and breathe them new life and create a new iteration where we combine our '04 classic, but with music and glitter and more camp. All of it feels really exciting."

While the movie musical won't look exactly like either of the previous Mean Girls iterations, Spivey assured fans that the new version isn't "trying to take away from what's already there."

"We're not trying to rewrite history, that we have just put our own spin on an already beloved classic. We love it just as much as you do," he said. "This is our tribute to that iconic piece. It's our tribute to Tina and the original cast. We hope you love it, but we're not trying to take away anything from the original. It's not a remake. It stands on its own. It's familiar, but it's not the same."

Mean Girls will hit theaters Jan. 12.

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