Union J's Josh Cuthbert has revealed he was attacked by three men on bikes who threatened to kill him.
Cuthbert said he was driving along a dual carriageway near his home when he was approached by people riding two Harley Davidson motorbikes.
He said: "One of them came right into my lane and turned his bike sideways towards me. I had to do an emergency stop to not hit into him.
"The other bike then came behind me and stopped his bike right behind my car, at this point my parking sensors were going nuts and I couldn't move the car at all, I was pinned in."
The 30-year-old went on: "Two of the guys then got off the bikes and one came to my driver window and one came to the front passenger window and were shouting 'Get the f*** out the car, get out the car now' over and over.
"I then shouted back saying I'm not getting out of the car. They then got even angrier / more aggressive and the guy on my right started to punch the window of my car numerous times (how the glass didn't break I have no idea) trying to get me out of the car."
Cuthbert said the men were in full bike gear, including helmets and visors, so he couldn't see their faces.
He said that made it "a lot scarier and more intimidating".
"The guy outside the passenger window was head butting the glass to try and break it but luckily had no luck either," he said.
"One of them said if I don't get out the car they were going to kill me (that was fun).
"It was honestly so terrifying, I was trapped and couldn't move. I couldn't even find my phone to call the police, because all my stuff flew everywhere after I did the emergency stop at the start of the attack."
Luckily, the star said other cars started to come along and the men got on their bikes and drove off.
"Just as they left they smashed my wing mirror off in anger," he said.
Cuthbert has reported the scary incident to the police but said his anxiety "has been through the roof since".
"I had a panic attack earlier when trying to leave the house," he said.
"Physically I am fine but it's been pretty rough emotionally/mentally. I'm praying these people are caught."
Cuthbert was on The X Factor with Union J in 2012 and they finished fourth.
However, six years later he quit the group.
Watch: Nicole Scherzinger is 'super proud' of putting One Direction together