He's already shot Equals, a thriller set in a world where emotions have been eradicated, which also stars Twilight's Kristen Stewart.
There was speculation that they might be more than just co-stars when the pair were spotted looking close and laughing together at the Venice Film Festival.
"I must've said something funny," Hoult offers, grinning. He describes the shoot as "phenomenal".
"Kristen and Drake [Doremus, the director] are two of my favourite people I've worked with, really inspiring to be around and I'm proud of the film."