Simon Cowell was testing out his new electric bike, also called an e-bike when he crashed and broke his back.
He was on his Malibu property on Saturday when the accident happened.
E-bikes can get up to 28 mph and even faster if the rider pedals.
In a statement his rep said, Simon had a fall from his bike on Saturday afternoon whilst testing his new electric bike in the courtyard at his house in Malibu with his family.
He was taken to the hospital where he will undergo surgery.