Simon Cowell is "sure" the members of One Direction will release solo material.

Simon Cowell

Simon Cowell

The group - Louis Tomlinson, Liam Payne, Harry Styles and Niall Horan - are currently enjoying an extended hiatus but their record label boss doesn't think they'll be taking too much time off from making music.

Asked if there will be "any more solo projects", he told E! News: "Yeah, there will be more, I'm absolutely sure of that."

The music mogul insisted the 'Drag Me Down' hitmakers needed a break after working so hard for the last five years.

He added: "Well, [the break] was always going to come. You can't work at that level; the way they did. I mean lots of things are going to be announced over the next few months, but they were, are, the nicest people, you know, to work with.

"Hardworking, appreciate everything, so it won't be the end."

Zayn Malik quit the group in March 2015 and has launched a successful solo career, and Simon thinks the 'Pillow Talk' singer is doing really well.

He said: "We were involved with what label he went on, and he's still signed to our company, so, he's done fantastic, and he's showing that he's a great vocalist and very talented."