Mariska Hargitay Reveals Bodybuilder Mickey Hargitay Wasn't Her Biological Dad in New Doc

Mariska Hargitay is done keeping secrets!

The 61-year-old "Law & Order: SVU" star is unveiling a documentary she directed about her Hollywood bombshell mom, Jayne Mansfield, in which she reveals that she's been "living a lie" by perpetuating a family secret about her paternity.

In "My Mom Jayne," which is about to have its North American premiere at the Tribeca Film Festival in NYC, the first-time director opens up about learning that her bodybuilder dad, Mickey Hargitay, was not her biological father.

In a new Vanity Fair interview, she says she decided there was no reason to keep up the facade anymore.

Hargitay found out 36 years ago that her biological dad is a retired Las Vegas showman named Nelson Sardelli, who is still alive and in his 80s.

When she was 30, she met with Sardelli, telling him, "I don’t want anything, I don’t need anything from you... I have a dad." Sardelli's reaction was much more tender: "I've been waiting 30 years for this moment."

She explains her tough approach as being all about her tight bond with Mickey. "There was something about loyalty," she says. "I wanted to be loyal to Mickey.”

In fact, when she asked Mickey — who died at 80 in 2006 — about Sardelli, he insisted he was her dad, and she honored his request that they never speak of it again.

Still, she didn't like "knowing I'm living a lie my entire life," and used her documentary to answer all the questions she still had. Sardelli participated in the film, as did Mariska's extended family.

Mariska's mom, Jayne Mansfield, was one of Hollywood's legendary blonde bombshells called the Three Ms, which included Marilyn Monroe and Mamie Van Doren. (Coincidentally, a documentary on the life of Van Doren, 91, from the filmmakers behind "Studio One" is currently shooting.)

Mansfield was memorably enamored of the color pink and cut an impressive figure with her bodybuilder hubby. The two were renowned for the ease with which they generated publicity.

Mansfield appeared in more than two dozen films, including "The Girl Can't Help It" (1956) and "Will Success Spoil Rock Hunter?" (1957), which usually highlighted her hourglass figure.

Just after midnight on June 29, 1967, Mansfield, her attorney and partner Sam Brody, a driver, three of her kids — including little Mariska — and her four Chihuahuas were in a car crash in Biloxi, Mississippi. The three adults and two of the animals died, leaving Mansfield's five kids motherless, a loss Mariska explores in "My Mom Jayne."

The process has been uplifting for her. She told Vanity Fair, “I grew up where I was supposed to, and I do know that everyone made the best choice for me."

“I’m Mickey Hargitay’s daughter — that is not a lie," she says of the secret she decided to share.

"My Mom Jayne" — which streams on HBO Max in June — plays Carnegie Hall Friday, June 13, at 7 p.m., featuring Hargitay in conversation with actor-director Griffin Dunne.