Vince Vaughn has decades of experience playing a variety of roles in movies. Yet, he was faced with a unique challenge in last year's Freaky, where the actor had to portray a young teen girl named Millie who is trapped in the body of a giant, middle-aged man. Celeste O'Connor, who played the role of Millies' friend, revealed in a recent interview that Vaughn would often consult her and his other young co-stars on how to play a teenager.

"It was amazing to be able to work with [Vince Vaughn] and learn from him as somebody who is so talented and so respected, especially in terms of comedy, because I'd never done comedy before. So I feel like I just learned so much from him, and also he was very open with us and receptive with all the young people. So it was really nice to be able to learn from him, and also that I felt like he was learning from us, because there was a lot of times where we would do like improv, and for Vince to be like, "Oh, what would a teenager say here?" I remember -- I think they put this in the movie -- the hashtags! When he was in the car, being like, "#stressed, #excited," that was something where we improved and we kind of bounced ideas off of each other. So it was really, really amazing to be able to work with him."
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Freaky tells the story of a serial killer known as the Blissfield Butcher, played by Vaughn, who enjoys nothing more than the brutal murder and dismemberment of his innocent victims. A freak accident with an enchanted dagger places the Butcher in the body of teen outcast Millie. While the Butcher is thrilled to have easy access to a fresh group of victims, Millie, trapped in the Butcher's former body, races against time to reverse the magical curse before the body swap becomes permanent.

Much of the comedy of the film is derived from watching Vaughn play Millie inside the Butcher's body. One of the most memorable scenes in the film has Vaughn's character enacting a complicated handshake with O'Connor's character. According to O'Connor, the handshake was something she made up on the spot with Vaughn on the day of the shoot.

"Honestly, we just came up with that on the day of! We improvised that. It took like hours and hours and hours to film that fight sequence in the kitchen, which was also another really fun day and a challenging day. At the end of that, Vince was like, "Oh, what something I could do with you guys that only us three would know how to do? Something muscle memory." And we were like, "Oh my god, handshake!" So we just made that up on the spot."

Directed by Christopher Landon, Freaky stars Vince Vaughn, Kathryn Newton, Celeste O'Connor, Misha Oshervich, Uriah Shelton, Alan Ruck, Katie Finneran, and Dana Drori. The film is now available digitally and on Blu-ray. Check out the entire interview at CBR.