Speaking to The Sun, the 18-year-old said that bosses have ordered him to join exercise classes following a series of back problems.
Styles said: "I have bad posture and I've been told to take Pilates once a week."
The 'What Makes You Beautiful' singer added that his spinal issues started as a result of a paper round he had as a child.
Meanwhile, bandmate Niall Horan revealed the extent of his own injury worries, saying: "I dislocated my knee playing football one time. When I got checked by the specialist I was told I've got a 67% chance of walking down the street and my knee dislocating itself."
Recent reports claim that Styles is being nurtured as the boyband's long-term lead vocalist.
> One Direction's Harry Styles spotted with Pixie Geldof at party
Watch the video for One Direction's 'One Thing' below: