Mariska Hargitay managed to keep a big family secret for decades — that her late father, Mickey Hargitay, was not her real dad. The Law & Order: Special Victims Unit actress’ late mom, Jayne Mansfield, had separated from Mickey in 1963 and had an affair with an Italian singer and performer named Nelson Sardelli, Mariska’s biological father. For decades, Mariska wasn’t ready to reveal the truth until she released her 2025 documentary, My Mom Jayne: A Film By Mariska Harigtay, which features appearances from her siblings and Nelson himself.

Below, Hollywood Life has gathered five facts about Nelson, his career, family and relationship with Mariska upon the release of her documentary.

Nelson Sardelli Is Italian but Was Born in Brazil

Nelson was born on September 20, 1934, in São Paulo, Brazil. His parents were from Italy.

Nelson Sardelli Worked at General Motors Before His Singing Career

While growing up in Brazil, Nelson worked for General Motors in an economic research and analysis job. During a past interview, he said he moved to Pontiac, Michigan, but mass layoffs were happening in the area. So, he briefly moved back to Brazil to work in construction, then returned to the U.S. to pursue his entertainment career.

Despite initially struggling to get a foothold in the business, Nelson began performing in Las Vegas and finally found success.

Nelson Sardelli Has Lived in Las Vegas Since the 1960s

Since 1965, Nelson has been a resident of Las Vegas.

Nelson Sardelli Is a Father & Has Been Married Twice

Nelson shares his daughters — Mariska’s half-sisters — with his late wife, Fledia Fay Sardelli, who died in 2012. He eventually remarried his new wife, Lorraine Sardelli.

Nelson Sardelli & Mariska Hargitay Have a Close Relationship

In her 20s, Mariska began to suspect that Nelson was her real father after someone showed her a photo of him, per Vanity Fair. Marisk’a late mother, Jayne, filed for divorce from Mickey in 1963 and had an affair with Nelson, but she reconciled with Mickey months before giving birth to Mariska in 1964.

Jayne died in a car accident in 1967. For years, Mariska, and the rest of the world, thought Mickey was her dad. While coming to terms with the truth, Mariska visited Nelson in Atlantic City, where he was performing, and introduced herself. Nelson emotionally told her, “I’ve been waiting 30 years for this moment,” but Mariska was guarded, she explained to Vanity Fair in May 2025.

“I went full Olivia Benson on him,” she said, referring to her Law & Order: SVU character “I was like, ‘I don’t want anything, I don’t need anything from you … I have a dad.’ There was something about loyalty. I wanted to be loyal to Mickey.”

Before releasing her doc, My Mom Jayne, in June 2025, Mariska held a private screening for Nelson’s daughters, whom Mariska had privately grown close to over the years.

“They just wept and wept and wept,” Mariska recalled during her Vanity Fair interview. “These two women that I love so much — I made them secrets! It’s so heartbreaking to me.” For decades, Mariska had introduced her half-sisters as “family friends.”

As for Mariska’s motivation in making the documentary? “I’m not good with lies. So, I also made this movie to unburden all of us,” she told Vanity Fair.