While Riley was eased into the role of Pinkie, it was a slightly different scenario on the set of his latest film, an adaptation of Jack Kerouac's On The Road, in which he plays Kerouac's autobiographical narrator, Sal Paradise.
"It was very intimidating to play Kerouac, or Sal Paradise, especially as an Englishman," he says. "And day one was a funeral scene," he grimaces.
The cast, including Twilight's Kristen Stewart, prepared for the film by attending 'Beatnik boot camp'.
"We all wore berets and moved around clicking our fingers," he jokes.
"It was an incredible experience. I'd never been to any of the places we went to. We went from Montreal to Chile to Argentina, Louisiana, Arizona, Mexico, Calgary, San Francisco."
But that meant spending more than five months away from his home in Berlin, which he shares with his wife, actress Alexandra Maria Lara, who he met on the set of Control.
"Yeah, it had to be like that for periods of time," he says. "When you're in a relationship and you're doing this weird job, you try and come up with a rule of being away for no longer than three weeks. It's not always possible."