The Green Knight Director Reveals What Made Him Cast Dev Patel Ever since his breakout role in 2009's Slumdog Millionaire, actor Dev Patel has taken on a variety of roles and earned immense acclaim no matter what project he might be starring in, and while his talents alone surely merit him being considered for exciting roles, The Green Knight director David Lowery recently confirmed one reason he met with the actor was realization of how cool he'd look riding a horse throughout the medieval tale. Of course, this was only how the casting decision started, with Patel's innate charm also offering the filmmaker an interesting opportunity to evolve the character in an unexpected way.