Naughty Boy has revealed he initially turned down the opportunity to work with One Direction.
The La La La hitmaker, who has written a few songs for 1D's new album, admitted he previously said no to collaborating with the X Factor boyband because he felt he couldn't make a contribution to their pop sound.
"I felt like I wouldn't have added anything to that sound. With this song, it was made for them," he said.
"I've written a song for them with Emeli Sande and Zayn, and they are going to record that. I think it's Simon's favourite song as well, so I've been told."
The 29-year-old producer added: "I think with this album, they can afford to be a bit more grown-up and more mature. They're boys turning into men so it's a good time for Naughty Boy to put a stamp on their sound. It's not a crazy step away from what you'd expect from One Direction but it's subtle enough."
Naughty Boy, whose real name is Shahid Khan, has been in the studio with 1D's Zayn Malik.
"I met him at the Brits and we both have similar backgrounds. We're both Pakistani, grew up in similar surroundings and culture, and it's good to meet someone you're on a level with," he said.
"I'd previously turned down working with One Direction but knowing Zayn and hearing him sing - he's also doing some writing - I thought, 'This guy's actually really talented'."
Naughty Boy - who is producing a track for Lynx's Make Beats Not War campaign, featuring Professor Green, Laura Mvula and Wilkinson - admitted he's been taken aback by the group's fans, known as One Directioners.
"It's just crazy. Whenever I work with him, there are people who camp outside the studio. They can find out his location. It's really intense stuff," he said.