Joan Collins and Elizabeth Taylor were two brunette beauties from England who had one thing in common – being with Conrad "Nicky" Hilton Jr.

Collins, 91, is speaking out in a new BBC documentary, "Elizabeth Taylor: Rebel Superstar," which is executive produced by Kim Kardashian. It looks at the life and legacy of the actress, who died in 2011 at age 79.

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Hilton, the hotel heir, was Taylor’s first husband. The "Cleopatra" icon claimed that he was abusive and, at one point, kicked her in the stomach, causing her to miscarry their child. He died in 1969 at age 42 from a heart attack.

Elizabeth Taylor in a black sweater posing with her first husband, Nicky Hilton, in a suit

Portrait of Actress Elizabeth Taylor (1932-2011) with her first husband, Conrad Hilton Jr., circa 1950. (GAB Archive/Redferns/Getty Images)

When Collins was asked if she ever dated Hilton, the "Dynasty" star replied, "I did. He was nuts."

"It was quite volatile," she claimed in the documentary, as quoted by People magazine. "Once we were lying in bed, and he took out this gun from the side table and shot it to the ceiling. Nicky Hilton had a problem with being too good-looking and too rich, and I don’t think he got a lot of love from his father."

According to the outlet, Taylor and Hilton married in 1950 when she was 18. It was far from a happily ever after.

"Once we were lying in bed, and he took out this gun from the side table and shot it to the ceiling."

— Joan Collins
Joan Collins in a white gown standing next to Elizabeth Taylor, who is wearing a light blue sparkling gown.

Joan Collins, left, is speaking out in a new documentary about Elizabeth Taylor, right, that is being executive produced by Kim Kardashian. (BAFTA via Getty Images)

"I was a bit of a punching bag," Taylor is heard in a voiceover, as quoted by the outlet. "And that’s when the reality of the world hit me. The reality is that I was not an adult, and I had to really grow up fast."

The couple divorced in 1951. Taylor would go on to marry seven more times, including to actor Richard Burton twice.

Collins dated actor Warren Beatty in the late ‘50s before she became a movie star. She married her fifth husband, Percy Gibson, in 2002. The producer is 32 years her junior.

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Joan Collins in a strapless dress standing next to Nicky Hilton in a tux.

Hotel heir Nicky Hilton and actress Joan Collins together at the premiere of the film "Heaven Knows, Mr. Allison," circa 1957. (Bruce Bailey/Archive Photos/Getty Images)

"First of all, we were great pals before we got married," the actress explained to Fox News Digital in November. "We worked together on a play… We enjoyed each other’s company. We hung out together. And we saw each other the following year. We wrote love letters – it was a gradual thing. And we realized that we were very much on the same wavelength."

"He is a really nice, kind, grounded person," she shared. "Many of the people that I’ve been with – and I’m not going to specify which ones – have been either neurotic, slightly unbalanced, or gotten into different things."

Critics have previously pointed out the couple’s age gap. But for Collins, it’s "just a number." She noted that it’s "never too late" to find love at any stage in life.

Actress Joan Collins wearing a leopard print dress on the patio of her San Tropez villa in the South of France beside her husband Percy Gibson

Joan Collins with her husband, Percy Gibson. (Eddie Sanderson/Getty Images)

"That’s how we both feel," she explained. "And we were friends first, above anything else."

She noted that they both share the same drive, which has been part of the secret behind their lasting union.

"I was born with a tremendous enthusiasm for life," she said. "My mother used to say that I never kept still when I was a child. I used to do five different things at once. I would be doing a crossword puzzle, making a doll’s house, reading, painting, trying to become a detective – all at once!"

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The cast of These Old Broads posing together and smiling.

Joan Collins and Elizabeth Taylor starred opposite Shirley MacLaine and Debbie Reynolds in "These Old Broads." (Timothy White/Disney General Entertainment Content via Getty Images)

"Life is a gift," she stressed. "That’s why they call it the present – it’s a gift. And so many people waste it. It’s so sad. It’s a gift, and it does not last for a long time."

Looking back at her life, Collins has no regrets – even after she and Beatty called it quits. Collins and Beatty began dating in 1959 and were engaged a year later before splitting.

Warren Beatty looking sternly at Joan Collins in a black and white photo of them

Joan Collins and Warren Beatty before she became a movie star. (Michael Ward/Getty Images)

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"We were both too young, too selfish, too ambitious," Collins reflected. "It just wasn’t right. I mean, I’ve had a lot of relationships. I had a lot of marriages. They don’t last. Luckily, you get older, and I met the man who’s the right person for me for the rest of my life. We’ve been together ever since. And we’re very, very happily married."

"Breakups happen," Collins shrugged. "It can happen based on different things."