By now, the secret’s out that several characters from 20th Century Fox’s superhero universe appear inDeadpool & Wolverine. One of those characters was Elektra, played by Jennifer Garner, in 2003’sDaredeviland2005’sElektra.

OnInstagram, Garner posted a training montage of how she prepared for her return as Elektra. “I was fit, but not Marvel fit,” Garner wrote in the caption. Having not picked up Elektra’s sais in two decades, Garner got to work on this “impossible dream,” preparing her body for a superhero transformation. With the help of her stunt double Shauna Duggins, Garner began incorporating weights, boxing, and peloton sessions into her workouts.

Deadpool and Elektra stand next to each other and stare.

A post shared by Jennifer Garner (@jennifer.garner)

Garner thankedDeadpool & Wolverinestar Ryan Reynolds and director Shawn Levy for her inclusion in the film. Garner previously worked with Reynolds and Levy onNetflix’sThe Adam Project,the movie where the duo pitched her theirDeadpool & Wolverineidea.

“I didn’t know that Elektra and I needed an ending, but Shawn and Ryan did. They are gifted in many ways, but seeing and elevating people around them is at the top of the list,” Garner wrote. “Shooting the fight was so fun, being there all together—truly like a dream. I’m proud of my friends and grateful to be up there with them. Thank you doesn’t cut it, guys, but it’s a good placeholder until I figure out what does.”

Garner wasn’t the only surprise appearance in the third Deadpool film. Dafne Keen as X-23/Laura, Channing Tatum as Gambit, and Wesley Snipes teamed with Elektra to help Deadpool and Wolverine fight Cassandra Nova in the Void. On his Instagram,Reynolds spotlighted each character, including Garner, whom he described as having a “blackbelt in nice.”

A post shared by Ryan Reynolds (@vancityreynolds)

Reynolds added, “I don’t care how talented someone is, you may’t hide humanity. She’s not only one of my favorite performers, she’s one of my favorite people.” Garner later thanked Reynolds again on Instagram stories, saying she would “fight bad guys” for him any day.

Deadpool & Wolverineis now in theaters.