Valerian and the City of a Thousand Planets Opens July 21.

French filmmaker Luc Besson usually gets things done quickly. But it took him more than a decade of care and attention to realize his cinematic dream Valerian and the City of a Thousand Planets.

The movie is based on the French comic books Valerian and Laureline by writer Pierre Christin and artist Jean-Claude Mézières. The series enthralled Besson as a child growing up in Paris. As a 58-yearold, he’s finally promoting the English language version of the sci-fi fantasy.

The Besson movie features Dane DeHaan as Valerian and Cara Delevingne as Laureline. They are a squabbling but in-love couple who are also space detectives assigned to uncover a lethal menace at the gigantic space station named City of a Thousand Planets. If they don’t find the device, it might destroy the city and maybe the universe.

But some of the city’s inhabitants — made up of separate spheres for humanoids, robots, methane aliens and marine extraterrestrials — aren’t in the mood to co-operate with the investigators.

Co-stars include Clive Owen, Ethan Hawke, Herbie Hancock, Rutger Hauer, Kris Wu and singer Rihanna, who stands out as a shape-shifting entertainer.

Certainly, Besson flirted with the fantasy genre in 1997 when he released The Fifth Element, to modest success at the box office. His latest effort is much more expansive and expensive.

The eye-popping designs and the state-of-the-art special effects are the real stars of the production, although the director admits during an interview that the casting of Valerian and Laureline were key.

“It’s almost a $200-million film and you know it’s going to be tough,” says Besson, who acknowledges that he has to compete with the trendsetting superhero movies. “So I start 10 years ago and I start very slowly.”

He hired 10 designers and then had them prepare separate space visions without really knowing what the goal was. “Weird” was the operative word, Besson says. “I received more than 6,000 drawings to start my puzzle and then I could think about my two (lead) actors.”

DeHaan was the Green Goblin in 2014’s The Amazing Spider-Man 2 and Delevingne portrayed the evil Enchantress in last year’s Suicide Squad, but they had more to offer than previous experience in a special-effects movie.

“I’ve known the comics since I’m 10 years old, so I really know Valerian and Laureline very well, so it was more for me like I had a picture of who I want, and then I check who can fit,” Besson says. “When I (met with) them the first time, the first hour of conversation, I knew it was them.”

The director wanted “the salt and the sugar in the same story” and that’s what he received from his headliners. Still, he had them do the onscreen chemistry test.

“So I have to wait a month to finally get them together and honestly, it takes 10 seconds,” Besson says. “After 10 seconds you can tell. I was so happy. I tried not to show it too much at the time, but I was so thrilled because I was sure about the couple.”

Casting the very busy Rihanna as the exotic dancer was more of a leap of faith.

Says the director: “I didn’t even know if it was realistic or not, but it was just my dream, and you never know until you ask.”

Apparently, his timing was just about right because Rihanna was considering making the transition into movies just like many of her music colleagues. Rihanna’s commitment meant a month of costume preparations for her and six days of filming some of the more complicated sequences in the film.

“She was exceptional,” Besson says. “When she was (on set), her entire entourage is out of the set. She was by herself. She was very focused and asking you to direct her, which for a director is a dream.“

Indeed, females make up a strong component of the film, as they usually do in Besson’s movies.

“I think it’s normal,” Besson says. “I pay the exact same attention, believe me, to the female part as I do to the male part … maybe I was raised a certain way that I was lucky enough to see that they’re both very strong.”

Typical, too, is the blend of comedy and drama, slapstick and action.

“Every time I try to get too serious, I have to crack a joke and I think my films are like this,” Besson says. “But I can’t just make a film like a cheeseburger and nothing (else).”