Singer Jason Derulo refused to quit working out after fracturing his neck earlier this year (12) and headed straight to the gym as soon as doctors gave him the green light.

The Whatcha Say hitmaker fell on his head while practising a high-energy dance routine for a concert in January (12) and he was diagnosed with a fractured vertebrae in his neck.

Derulo was forced to scrap his tour and wear a protective brace as he recovered, but the star couldn't wait to get back into shape and resumed his exercise regime when it was deemed safe enough for him to work out again - and his motivation helped to inspire his girlfriend, Jordin Sparks, to rev up her gym routine too.

Sparks tells New York radio station 92.3 NOW, "As soon as the doctor said it was OK for him to be in the gym, he was in there - broke neck, neck brace and everything - in there trying to lift weights. He was on an exercise bike and doing weights at the same time because he couldn't run. I was like 'I gotta step my game up!'"

The scary incident has prompted Sparks to ban her beau from performing the same dangerous stunt again: "As long as I'm living, he will never attempt another back-tuck!"

But there was one positive aspect of his injury - it brought them closer together.

She says, "That's when we started getting really close. When he broke his neck, he needed help with a lot of things and I tried to be there as much as I could."