It's been over a year and a half since One Direction went on hiatus, with their legion of fans around the world waiting on tenterhooks for news regarding their comeback. Well Directioners, Simon Cowell has some news for you.

The band's X-Factor mentor has a theory, which he explained to The Sun, that the group may reunite despite their varying success as solo artists, but added that Harry Styles may not be involved.

"You know, it's fun being out there on your own but what I hope is going to happen is that they remember now how much fun it was being in a group," he said, presumably thinking about enormous piles of money.

"I always believe that you don't make rules, you break the rules. So there's nothing to stop them, if they want to, getting together for a tour, for an album. I made it absolutely clear, obviously, 'We're in'."

On the possibility of Styles not returning, Cowell admitted "it wouldn't be the same", also adding that Zayn Malik could "100%" return to the group despite him leaving the band in March 2015 to be the first to pursue a solo career.

Malik released his first solo album in March 2016, led by the single Pillowtalk. Horan's first single, This Town, debuted in October while Tomlinson teamed with DJ Steve Aoki for Just Hold On, which he debuted at the X-Factor grand final last year.

Styles' first solo effort arrived in May 2017. Sign of the Times was the lead in to the singer's self-titled debut album, but it's not just music that's been keeping the most popular member of the band busy.

He made his acting debut in Christopher Nolan's World War 2 epic Dunkirk last month, and does a pretty good job as one of the young soldiers trapped on a French beach awaiting rescue. Ahead of the release of the film, writer and director Nolan revealed he didn't really know who Styles was when he cast him.

"I don't think I was that aware really of how famous Harry was," he told The Hollywood Reporter. "I mean, my daughter had talked about him. My kids talked about him, but I wasn't really that aware of it. So the truth is, I cast Harry because he fit the part wonderfully and truly earned a seat at the table."

With Liam Payne, Niall Horan and Louis Tomlinson all still busy with their various solo projects (Payne's is fatherhood), any reunion would still be some way off happening. Stay patient One Direction fans.