In 2015, Petsch auditioned for a role on The CW's Legends of Tomorrow. Although the casting director, David Rapaport, loved her, he wanted her for the pilot he was casting. A week later she met with the producers to audition to play Betty. However, Rapaport quickly notified her that she was actually auditioning for a different, secret role. "'You're obviously not auditioning for Betty; it's for another part that I can't tell you about yet. You look exactly like I imagine her to look, and you've got the presence,'" he told Petsch.