Simon Cowell is desperate for One Direction to get back together.

The 'X Factor' boss - whose record label Syco managed the boy band for five years - was devastated when he was told the group was planning to take an extended hiatus last year and is now trying to push for them to reunite and become ''bigger than ever.''

A source told The Sun Online: ''He so proud of Louis [Tomlinson] and all the group's achievements over the last 18 months. For them all to launch solo careers - and be a group of superstars individually as well as in the band - makes him so proud.

''It also makes Simon more determined than ever that the hiatus was not the end of One Direction. Simon has always regarded the band as being on a break, rather than over, and although there are no confirmed plans at the moment for them to get together again, it is his ambition and belief that the guys will get be reunited.''

Shortly after they went their separate ways, Harry Styles announced he was releasing his debut solo single 'Sign Of The Times', which reached Number 1 in the charts. Liam Payne then dropped 'Strip That Down' and Niall Horan released 'Slow Hands' and, although they're doing so well on their own, the 57-year-old music mogul is hopeful their success will encourage them to get back together in the near future.

The insider explained to the publication: ''In Simon's eyes, the best example for One Direction to follow has always been The Rolling Stones - with the guys doing their own successful solo projects and then getting back together regularly. This is now Simon's ultimate dream for One Direction.''