French singer Cécile Corbel, a big fan of Studio Ghibli's films, had sent the studio her second album as a gift back in 2009. Toshio Suzuki listened to it, was seduced and thus decided to hire her to compose the film's score.
Nervous at the idea of directing the film himself, Hiromasa Yonebayashi would initially always seek Hayao Miyazaki's advice and opinions. He eventually realized he was on a journey he should face alone when the time came to draw the storyboard, and Miyazaki congratulated him for it.
There are two English dubs. There is a British English dub distributed by StudioCanal released in 2011 in the United Kingdom and the Disney dub in the United States released in 2012. One year after the Japanese release and the StudioCanal dub is mostly recommended.