Jeri Ryan took the role of the ex-Borg drone Seven of Nine on Star Trek: Voyager and made a fan-favorite character out of it. When Voyager ended, we thought we'd never see Seven of Nine again, but Star Trek: Picard changed all of that, allowing the character to return in the first season of the new series. Not only that, Ryan stayed for all three seasons of Picard, and Seven of Nine became the captain of the new Enterprise in the series finale. Fans are still hoping her journey will continue in the spin-off series, Star Trek: Legacy.
To say this character has been successful is an understatement, but Ryan had trepidation about taking on the role. After reading for the producers, she was invited back for a screen test. According to a quote included in The Fifty-Year Mission The Next 25 Years from The Next Generation to J.J. Abrams by Mark A. Altman and Edward Gross, Ryan thought she should probably watch an episode of Voyager before she committed to a seven-year contract. So she and her mother watched together, and Ryan described it as "the worst hour of TV I'd ever seen." She'd even watched the episode through her fingers as she had both hands over her eyes.
After the episode ended, Ryan told her mother she couldn't screen test, and she called her agent to cancel, thinking that was the end of that. But Rick Berman called her the next morning and invited her to come in and talk over her fears and reservations. During the conversation with Berman, Jeri Taylor, and Brannon Braga, Ryan told them what episode she'd watched, and they were all in unison that the series shouldn't be judged by that episode, which wasn't identified, though it probably isn't difficult to extrapolate which one Ryan saw! After being reassured about the vision the team had for her character, Ryan went on to agree to play Seven of Nine, and the rest is Star Trek history.