Gwyneth Paltrow has claimed multiple times that she had been the "victim" of a ski crash as she began giving evidence in her trial in the US state of Utah.
The Oscar-winning actress said she did "not believe" the testimony of previous witnesses and that her version of events was "categorically" the truth.
Ms Paltrow is being sued by retired optometrist Terry Sanderson over a collision at the Deer Valley resort in Utah in 2016.
She is accused of "slamming" into Mr Sanderson on a ski slope and falling on top of him, leaving him with several broken ribs and a severe concussion.
Ms Paltrow has denied the allegations, claiming that Mr Sanderson collided with her, and is countersuing him. She has also denied that she is counterclaiming for one dollar because of a similar "symbolic" lawsuit brought by US pop star Taylor Swift.
The actress began her evidence by describing herself as an "intermediate" skier who was "familiar" with the rules of skiing.
She denied that she had been engaging in "risky behaviour" on the day of the collision and alleged multiple times that she had been skied into from behind by Mr Sanderson.
"I was confused at first and I didn't know exactly what was happening," she said, describing the incident.
"It's a very strange thing to happen on a ski slope. I froze and I would say I got very upset a couple of seconds later."
She added: "(I thought) Is this a practical joke? ... My mind was going very quickly and trying to ascertain what was happening."
Ms Paltrow acknowledged that neither her ski instructor nor her children had seen the incident and did not remember fellow skier Craig Ramon being on the scene.
Mr Ramon previously gave evidence at the trial, in which he alleged he had witnessed the actress "slam" into Mr Sanderson.
"I did not believe his testimony," Ms Paltrow said.
"I don't believe he saw what he thinks he saw. He said he was 40 feet away and colour blind.
"If you have two people in ski gear with helmets on and you're 40 feet away I don't know how you can discern who is who."
She added: "What you have to remember is that when you're a victim of a crash, your psychology is not necessarily thinking about the person who perpetrated it."
"Mr Sanderson hit me and that is categorically the truth," the star claimed.
The trial, in Park City, Utah continues.
Source: Press Association
