Sometimes I see people finish a film and they go, "Yeah, that was good. Where are we going to eat?"

I won't be able to do a film just for bad reasons, for money or for - I just can't. If I have one more where I feel I can bring you something, I will do it.

We talked a lot with the musician. And for now there are few options, and I give him few weeks to come and surprise me with something. I don't want to start and say, okay here is what I want. Because maybe he has an idea that is better than mine.

I saw Cara Delevingne like five, six times. And I was never talking about the film [Valerian]. And then at the end, I say okay, let's do some test. She says yeah, yeah, good. So I took her in the room, and I test her for like six hours non-stop. Exercise, exercise, exercise for six hours. It was actually funny. And then I knew at the end of the six hours.

I did The Fifth Element and [Jean-Claude] Mezieres, the artist of Valerian; he was working on Fifth Element. And he's actually the one who say, why don't you do Valerian? And I said because we can't make it. And you really have to wait for Avatar and to suddenly think oh okay, maybe we can think of it. But before Avatar, just forget it.

For example, in your house, you have the heater on the ground itself. Here, it's the gravity. No matter where you are, that's where the gravity is coming from. It's almost like a carpet that you put down. If you're on the other side, it doesn't matter to us because we're still walking on the ground. Actually, at the beginning of the film [Valerian], we see when they install the gravity system.

My biggest surprise is probably the level of involvement of all the artists [in Valerian] who participated at every level.