The project has been on a rollercoaster for years, but things seemed to look up when Tatum came on board as the star and producer in 2015. Director Rupert Wyatt was attached, but then dropped out. He was replaced by Doug Liman. After some work on the script, Liman also dropped out, to be replaced by Gore Verbinski.
Details of Caplan's character are unknown, but some fans are speculating she could play Belladonna Boudreaux, the mutant leader of the Guild of Assassins -- which rivaled Remy LeBeau's own assassins group in New Orleans. In the comics, she's also a love interest of Remy/Gambit.
Caplan next appears in "The Disaster Artist" with James Franco.