When "On Swift Horses" played as a secret screening at the Palm Springs Film Festival in January, at least half a dozen people walked out, not because it's bad, but because a certain contingent of the normally open-minded art-house audience hadn't signed up for a gay love story.

Daisy Edgar-Jones modeled a fresh-off-the-runway Gucci look at South by Southwest on Friday for the premiere of "On Slow Horses," a romantic drama film also starring Jacob Elordi, Will Poulter, Diego Calva and Sasha Calle.