One Direction forced to get fit ahead of world tour
The band's management are reportedly worried that Louis Tomlinson, 20, Harry Styles, 18, plus 19-year-olds Niall Horan, Liam Payne and Zayn Malik aren't fit enough to take on their mammoth eight-month run of shows in December.
A catalogue of injuries have blighted the boys in recent months - and bosses want to put a stop to it.
A source told the Daily Mirror: "We're concerned about them - and Liam is still healing after he broke his toe when his MacBook fell on it this summer in the US.
"Zayn and Niall have both been on crutches so now they're all on hardcore fitness regimes."
These lads are an accident-prone lot - Irish cutie Niall has dislocated his knee no less than 14 times, while Harry was recently forced to take up Pilates to improve bad posture brought on by his high school paper round.
1D have found huge success around the world since coming 3rd on X Factor in 2010.
They made chart history in March when they became the first ever British group to go straight to No 1 in America with their debut album, Up All Night.
Between them they have tens of millions of followers on Twitter and are widely considered the biggest band in the world.
The band recently admitted that they enjoy the attention they get from their hugely loyal fanbase when they play a gig.
Niall told Vogue: "I love it. I love the screaming.
"They love it, too: they’ve all got their tickets and they’ve been waiting a year or so to see you, so you’ve got to give it your best."
But Harry Styles - probably the most popular member with the ladies - is still getting used to his sex symbol status.
He admitted: "You’re never going to get used to walking into a room and have people screaming at you.
"There’s a lot of things that come with the life you could get lost in. But you have to let it be what it is. I’ve learnt not to take everything too seriously."