One Direction put on an energetic display as they hit the stage in Detroit... as manager Simon Cowell reveals band's split was 'world's worst kept secret'

Fans were left heartbroken when it was confirmed One Direction would be taking an extended hiatus next March.

But Simon Cowell claims he's always known the bans were planning a temporary split and has been drip-feeding the news to their young supporters by dropping hints over the past year.

The Syco music manager's comments come as the boys - Harry Styles, Liam Payne, Louis Tomlinson and Niall Horan - performed at Ford Field in Detroit, Michigan on Saturday as they continue their On The Road Again Tour.

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On The Road Again: One Direction star Harry Styles was on top form when he performed at Ford Field in Detroit, Michigan on Saturday

On The Road Again: One Direction star Harry Styles was on top form when he performed at Ford Field in Detroit, Michigan on Saturday

Despite their relentless schedule and the demands of a big arena show, 1D were as energetic and enthusiastic as ever as they bounded out onto the stage.

The pop heartthrobs were their usual optimistic selves as they powered through their biggest hits including Steal My Girl and What Makes You Beautiful, thrilling their army of devoted fans.

It was a special concert since Liam was celebrating his 22nd birthday, with Niall describing the show as Liam's very own 'birthday party' and joking about his 'birthday suit'.

The boys are back in town: Liam Payne, Niall Horan and Louis Tomlinson delivered a lively set 

The boys are back in town: Liam Payne, Niall Horan and Louis Tomlinson delivered a lively set 

'Worst kept secret': The boys' concert comes as their music manager Simon Cowell revealed he's been dropping hints for a year about 1D's impending hiatus

'Worst kept secret': The boys' concert comes as their music manager Simon Cowell revealed he's been dropping hints for a year about 1D's impending hiatus

Birthday boy: Liam was celebrating his 22nd birthday with the help of thousands of screaming fans 

Birthday boy: Liam was celebrating his 22nd birthday with the help of thousands of screaming fans 

Can't drag them down: The lovable lads bounded across the stage as they belted out their best hits 

Can't drag them down: The lovable lads bounded across the stage as they belted out their best hits 

Loving life: Liam looked like there's nowhere he would rather have been than with his fans 

Loving life: Liam looked like there's nowhere he would rather have been than with his fans 

Final months: The boys are schedule to go their separate ways next March, but Simon is confident they will get back together in future 

Final months: The boys are schedule to go their separate ways next March, but Simon is confident they will get back together in future 

The boys, who have been on top form despite the departure of fifth member Zayn Malik this spring - were dressed down in their favourite casual jeans and T-shirts for the stellar show.

Meanwhile, music boss Simon has revealed he has known for months the boys would be taking a long hiatus, but was worried about breaking the news to their fans.

'I kind of hinted a few months ago they’d be having time off', the 55-year-old star told the Sunday People. 'It was the world’s worst kept secret.'

Moves like Jagger: Harry performed a funny dance on stage as he serenaded his screaming fans

Moves like Jagger: Harry performed a funny dance on stage as he serenaded his screaming fans

Curly crop: The 21-year-old hunk's mop of hair was looking more voluminous than ever
Curly crop: The 21-year-old hunk's mop of hair was looking more voluminous than ever

Curly crop: The 21-year-old hunk's mop of hair was looking more voluminous than ever

Mobbed: Simon blamed the mass hysteria that accompanies their every move for their need to take a break 

Mobbed: Simon blamed the mass hysteria that accompanies their every move for their need to take a break 

Going solo: Harry is expected to launch a  music career while the others will be busy with their own projects

Going solo: Harry is expected to launch a music career while the others will be busy with their own projects

Simon revealed the boys' intense touring schedule and the fan hysteria that follows them everywhere they go had left them exhausted.

'We’ve said to them take as long as you want and, within reason, do whatever you want', he explained.

The X Factor boss, who put the boys together as a group on the ITV show back in 2010, also revealed that he'd had little contact with Zayn since his decision to leave, insisting that his main responsibility was to the group as a whole.

Father-to-be: Louis is said to be concentrating on his personal life after it emerged he was set to welcome a child with former fling Briana Jungwirth

Father-to-be: Louis is said to be concentrating on his personal life after it emerged he was set to welcome a child with former fling Briana Jungwirth

Musical man: Guitar-loving Niall is also rumoured to be plotting a solo career 

Musical man: Guitar-loving Niall is also rumoured to be plotting a solo career 

Touch of home: Niall's microphone was decorated with the Irish flag 

Touch of home: Niall's microphone was decorated in the colours of the Irish flag

TV role: Louis is set to be a judge on Sony's Be In The Band and previously revealed he'd love to sit on The X Factor panel 

TV role: Louis is set to be a judge on Sony's Be In The Band and previously revealed he'd love to sit on The X Factor panel 

Fan favourites: One Direction were shown a whole lot of love from their American fans 

Fan favourites: One Direction were shown a whole lot of love from their American fans 

Show of support: Teen girls proudly showed off their homemade signs before the concert began

Show of support: Teen girls proudly showed off their homemade signs before the concert began

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