Rebel Wilson used her martial arts training when preparing for the action sequences in Pitch Perfect 3.

The Australian actress reprises her role as Fat Amy in the third installment of the musical comedy film franchise, which follows all-girl a cappella group The Barden Bellas as they reunite for a performance in an overseas United Service Organizations (USO) tour.

While Pitch Perfect 3 is focused on The Bellas' concerts, there is a side plot in which Amy is forced to confront a series of attackers, which Rebel was ready to tackle as she already has some fight training under her belt.

"When I was 18, I went in an all-style martial arts free fighting tournament, I trained for six months," she said during an appearance on The Tonight Show Starring Jimmy Fallon on Tuesday night (19Dec17). "I really liked that show Teenage Mutant Ninja Turtles as a kid, and I think I thought it was going to be fun like that."

Rebel also explained that she once traveled to Johannesburg, South Africa for a competition. Though the fight was a laugh initially, it quickly turned into an emotional experience for the star.

"I was having fun at first and then the referee blew his whistle and it was the end of the first round so I went to go back to my corner, and as I turned and looked away (my opponent) smacked me right in the middle of my face and then I started crying, hysterically crying, and I said, 'I want to quit the fight,' because it was just a joke, I didn't mean to be there," the 37-year-old recalled. "And then my Sensei (teacher) said, 'You can't quit, it will bring shame on the Dojo (school)... so I had to let the girl hit me, clear punches, three more times. Then I cried for three hours straight."

Thankfully, Rebel had a much easier experience when showing off her moves in the new film - but she did accidentally hit some of the stuntmen on occasion.

"When I did, they said it didn't hurt that much. One guy described it as like a kiss," she laughed.

In addition to the interview, Rebel and host Jimmy sang several Christmas songs, though there was a twist, as the lyrics had been run through Google Translate. The pair performed hilarious takes on tunes like Deck the Halls and Winter Wonderland.