George Michael was treated for minor injuries following an accident on the M1 last week.
A passing motorist has revealed the 49-year-old was left covered in blood after taking a tumble from a silver Range Rover, which was driving at around 70mph as he tried to close its door properly.
Katherine Fox, 23, said: "I saw blood everywhere and a man on the ground.
"I thought someone had run across the road and been hit.
"I asked what had gone on and was told he tried to open the car door and shut it again because it wasn't shut properly and apparently fell out at 70mph.
"I was on the phone to the ambulance and said, 'You'd better come quick. This doesn't look good'.
"George was wearing a black and gold Adidas tracksuit that was ripped all down the arm and shoulder. He had no trainers on.
"I grabbed one from the second lane because cars were swerving to avoid it.
"His sunglasses were also in the road. I could hear the crunch as cars drove over them."
George was travelling with friends on a four-lane stretch of the motorway, who pulled on to the hard shoulder and ran across two lanes of traffic to help the star when he fell, while Katherine reversed her own vehicle to shield him from passing traffic.
Katherine thinks George is "lucky" to be alive and believes the accident could have been much worse.
She told The Sun newspaper: "George didn't say anything, he just seemed in shock.
"He was sitting down against a car and in the arms of his friend.
"The guy holding him was quite scared. He kept saying to George, 'Are you all right mate?'
"I think George was lucky he didn't die.
"If he'd landed in the second lane he would have been hit by a car without a doubt.
"He was in the middle of the M1. I could have run him over."