Troubled pop star George Michael was caught falling asleep while driving on Thursday night, before suddenly waking up and careering into a bollard. The former Wham! heart-throb received a police caution in March for possession of cannabis after he was found slumped at the wheel of his car in central London in February. The gay singer was driving in Highgate, north London, near his home when he dozed off at traffic lights, which changed four times before he was woken up by another driver tapping on his window. The driver tells British newspaper the News Of The World, "He was sweating heavily and had his iPod on. That's probably why he didn't hear all the angry tooting behind him. He got going again but was weaving all over the place. Then he hit a bollard. I doubt he even noticed it. He looked wasted. He just drove on."