‘Little House on the Prairie’ child star sets the record straight on ‘mortal’ enemy Melissa Gilbert

Alison Arngrim was never "nasty" to her co-star when cameras stopped rolling.

The former child star, who played mean girl "Nasty" Nellie Oleson on "Little House on the Prairie," celebrated the show’s 50th anniversary over the weekend at Big Sky Ranch in Simi Valley, California. It is where the series was filmed during its nine-season run from 1974 to 1982.

Among those in attendance was Melissa Gilbert, who starred as Laura Ingalls Wilder. While Oleson was famously a bully to Gilbert’s character, Arngrim insisted that in real life, they were more like "sisters" than rivals.

‘LITTLE HOUSE ON THE PRAIRIE’ STAR MELISSA GILBERT ON EMBRACING A SIMPLER LIFE: ‘I DON’T MISS HOLLYWOOD’

"Here’s Melissa Gilbert and I playing mortal enemies, beating each other senseless all week," the 62-year-old told People magazine. "And then on the weekends, we’d go to each other’s house for a slumber party, and we were hanging out."

Arngrim noted they even had fun choreographing their fight scenes together.

"It’s so completely bonkers," she told the outlet.

Arngrim previously told Fox News Digital that she and Gilbert, 59, were pals.

"We’d beat each other up all week and then go to each other’s houses for slumber parties and make fudge and watch TV," she said.

During the festival, Gilbert shared her memories of co-star Michael Landon. The actor, who played patriarch Charles Ingalls, died at age 54 from pancreatic cancer in 1991.

The actress described how Landon would go out of his way to make the cast happy.

"Every year for NBC, he would announce the Rose Parade and instead of taking a payment for that, he would use that money to buy the cast and crew Christmas presents," Gilbert told the outlet.

"So he sacrificed his New Year's Eves, basically, to be at the Rose Parade at 3 a.m. so that he could give us all really amazing Christmas presents," she added.

Gilbert described the star as "a father figure," one whom she developed a close bond with.

"My own father passed away when I was 11," Gilbert reflected. "And I had been working with Michael for two years at that point, and he really sort of stepped in and kind of watched over me in a much more paternal way."

"These people are here because he wrote this show and directed it and produced it, and I know that he would be incredibly proud if he could see this," she shared."This is his legacy. A hundred percent."

Leading up to the festival, Arngrim told Fox News Digital that Landon was a straight-shooter who battled insecurities.

"Michael, in many ways, was a Hollywood person," Arngrim explained. "Yes, he owned a Ferrari. He had fast cars. But… the show was therapy for people. And I believe it was therapy for Michael in a lot of ways… [What surprised me] was that… insecurity, because he was so powerful. He was the executive director. He was the producer. He was the writer and star of the show. He was everything. He was loved by millions, absolutely gorgeous, very much in charge… He’d be cracking jokes. He had a wonderfully twisted, warped sense of humor. He was hilarious."

"But you could see that there were moments when he was trying so hard, ‘Will this be good enough?’" Arngrim continued. "He wanted it to be good enough to be perfect. And you could see that there were times when he’d get that look like, ‘Oh, my God, maybe this isn’t going to be perfect.’ And I think that was maybe the thing that drove him, maybe scared him. That it wouldn’t be perfect."

Decades later, Arngrim still views the beloved patriarch as "complicated and fascinating."

"That was the most fun you could have on a set without getting arrested," she said. "[He was all about] the jokes, the foolishness, always wanting to make the kids laugh… and then being very supportive and respectful at the same time. And then being an absolute task master… all at the same time, all day long. I don’t think I’ve met anybody [else] quite like him."