Gwyneth Paltrow is in a US court as a civil trial begins over claims she seriously injured a man in a skiing accident in Utah in 2016.
The actress is being sued by retired optometrist Terry Sanderson, who has alleged Paltrow crashed into him at a resort in Park City.
He claims she skied "out of control", causing "a brain injury, four broken ribs and other serious injuries".
Paltrow has counter-sued, claiming he hit her with a "full body blow".
Opening statements in the jury trial began on Tuesday, with proceedings scheduled to last for eight days. The 50-year-old Oscar winner and her children are expected to testify.
Sanderson, 76, is seeking damages of US$300,000 ($484,339), after dropping a previous claim for US$3.1 million.
The incident occurred in February 2016 on the beginners' slope at the Deer Valley resort where Paltrow was skiing with family.
The case appears to hinge on which skier - Paltrow or Sanderson - was uphill at the time of the accident. According to Deer Valley's safety policies, the skiers "ahead or downhill of you have the right-of-way. You must avoid them".
During opening statements, Paltrow's lawyer Steve Owens told the jury his client had just begun descending the slope when a pair of skis suddenly appeared between hers and a man collided with her back.
Paltrow's lawyer argued Sanderson, who suffers from vision and hearing loss as a result of a previous stroke, may not have seen his client before he collided with her.
Owens said his client initially suspected she was being assaulted and was so shaken by the incident she chose not to ski for the rest of the day.
"She may have sworn at him. It rattled her and it physically hurt her," he said.
But lawyers representing Sanderson argued it was, in fact, Paltrow who had been skiing erratically that day because she was trying to watch her children go down the slopes.
Sanderson's lawyer, Lawrence Buhler, said Paltrow showed "conscious disregard for other people on the mountain" when she crashed into his client, causing severe injuries, including four broken ribs and permanent brain damage.
"Distracted skiers cause crashes," he said, noting that Paltrow is a seasoned skier and is well aware of the rules. "She knew that skiing that way, blindly skiing down a mountain while looking up and to the side was reckless, she knew that continuing to ski that way ... she would crash into somebody below her."
The original claim, filed in 2019, said: "This case involves a hit-and-run ski crash at Deer Valley, Utah, where defendant Gwyneth Paltrow skied out of control and hit the back of Terry Sanderson, another skier, who was downhill, knocking him down hard, knocking him out, and causing a brain injury, four broken ribs and other serious injuries.
"[Ms] Paltrow got up, turned and skied away, leaving Sanderson stunned, lying in the snow, seriously injured."
The filing also claimed a ski instructor who had been training Paltrow, saw Sanderson injured but also made no attempt to help him.
In court on Tuesday, Paltrow's lawyers disputed this claim and argued both a ski instructor and a ski patrol rushed to render aid after the incident.
Sanderson previously said he waited for almost three years to file the lawsuit because he could not function properly due to the concussion, and also because he had some problems with lawyers.
Paltrow later filed a counterclaim, alleging Sanderson had hit her, adding that he had apologised to her and said he was fine.
Her counterclaim seeks $1 in damages plus legal fees.
-BBC