“New Moon” star Taylor Lautner suffers from restless leg syndrome. The 17-year-old has Wittmaack-Ekbom’s syndrome, meaning he has a relentless urge to move his legs.
He explained to Star magazine, “I can never stop bouncing my knee. People always tell me to stop, but I can’t force it to stay still. If we’re in the car, I’ll end up shaking the whole car.”

Could the video that Alison posted where Taylor talks about his shaking leg help confirm this?

Source