"We were on this cattle truck and these men came on another truck with a lot of guns. [They pulled up beside us] with the big guns and they were like, 'Yeah, you've got to get off your truck.'" she said.
Wilson said the group was then taken to a house and held overnight.
"I felt like I was very good in the crisis. I was like a team leader," she added.
"They sat us down, and I said, 'Everybody link arms,' because I was petrified in the night that they might want to take one of the girls or something."
Wilson said they were set free the following day.
"They came and said, 'Your truck is ready now. You can go, go, go,'" she said.
"We just got back on that truck and got out of there and crossed the South African border a few hours later."
While she still doesn't know why the kidnapping happened, Wilson has developed her own theory.
"I think maybe those guys, maybe, used us to smuggle illegal things in the bottom of the truck," she added.
She did not specify when the incident happened.
Wilson and Middleton filmed the edition last year, which sees the pair bond as they travel around Mexico with only a 4x4 and their backpacks.
Wilson made headlines last year for her astonishing 30kg weight loss, dubbing 2020 "the year of health".
She said how her 40th birthday, as well as suffering mental health issues over Hollywood's attitude to weight, had encouraged her decision to make healthier choices.
"Weirdly this year was always going to be the year of health. I've been naming my years now, and, that's kind of having these resolutions but for the whole year.
"It's not like I want to lose weight and get to a certain number. It's more than that.
"It's about dealing mentally with why I was overeating and I had a job where I was paid a lot of money to be bigger at times, which can kind of mess with your head a bit."
