Luc Besson is assembling a rather interesting cast for Valerian, his ambitious sci-fi epic based on a French graphic novel series. In addition to Dane DeHaan, Cara Delevingne and Rihanna (seriously), the film has just acquired Ethan Hawke. While the actor definitely has plenty of sci-fi on his resumé, it’s kind of surprising he hasn’t appeared in a Besson film just yet, since it seems right up his alley.

Besson himself reveals that Hawke is the latest to join the cast of Valerian, based on Pierre Christin and Jean-Claude Mézières’ French graphic novel series, which was first introduced in 1967.

There are no details on Hawke’s role in the film, which stars Dane DeHaan and Cara Delevingne as Valerian and Laureline, spatio-temporal agents who protect the future from rogue time travelers. Here’s the official description of the first novel in the long-running series:

Galaxity, capital of the Terran Empire in the 28th century. Valerian and Laureline are agents who protect mankind from rogue time travellers. Now they are sent to New York in 1986 to intercept Galaxity’s worst megalomaniac, Xombul-except that in 1986, the world is in ruins and New York is about to be swallowed by the ocean. The two agents must navigate the shifting waters of the past to make sure that the future will exist.

The high-concept film features five primary human characters and an assortment of aliens and creatures, with Clive Owen portraying Commander Arun Filitt, while details on Rihanna’s role are unknown, though Besson promises it will be “big.” Fingers crossed that she gets to play a badass villain.

The Valerian series concluded in 2010, and Besson has been developing his big screen adaptation for years, previously scrapping a draft of the screenplay after he saw James Cameron’s Avatar.

Hawke recently reunited with Gattaca director Andrew Niccol for last year’s Good Kill, and received his fourth Oscar nomination earlier this year for Richard Linklater’s Boyhood. He stars next opposite Emma Watson in the horror film Regression, and appears in Antoine Fuqua’s The Magnificent Seven.