Mariska Hargitay is done playing detective with her own past.

At 61, the iconic figure from Law & Order: SVU is making her directorial debut. She is stepping behind the camera to create a personal and revealing documentary about her legendary mother, Jayne Mansfield. This project will also serve as a platform for her to open up about a family truth that she has kept secret for many years.

In My Mom Jayne, premiering at the Tribeca Film Festival before hitting HBO Max in June, Hargitay reveals that the man who raised her, famed bodybuilder and actor Mickey Hargitay, wasn’t actually her biological father.

“I don’t want anything, I don’t need anything from you… I have a dad,” she recalls telling her biological father, retired Las Vegas showman Nelson Sardelli, after tracking him down at age 30. Sardelli, now in his 80s, responded with emotion: “I’ve been waiting 30 years for this moment.”

In a new interview with Vanity Fair, Hargitay explains why she’s telling the truth now: “There was something about loyalty. I wanted to be loyal to Mickey.” After confronting him years ago about the rumors, Mickey insisted he was her father — and asked her never to bring it up again. She honored that request until now.

But keeping the truth inside came with a cost. “I didn’t like knowing I’m living a lie my entire life,” she admits, calling the documentary process “uplifting.”

“I grew up where I was supposed to, and I do know that everyone made the best choice for me,” she reflects. “I’m Mickey Hargitay’s daughter — that is not a lie.”

The documentary also explores the glamor and tragedy of Jayne Mansfield’s life. A Hollywood sex symbol of the 1950s — one of the “Three Ms” alongside Marilyn Monroe and Mamie Van Doren — Mansfield made a splash with roles in films like The Girl Can’t Help It (1956) and Will Success Spoil Rock Hunter? (1957), all while building a pink-soaked public image and tabloid-friendly romance with Mickey.

But her life ended in heartbreak. On June 29, 1967, Mansfield, her partner Sam Brody, a driver, three of her children (including a young Mariska), and four Chihuahuas were involved in a car crash in Mississippi. The three adults and two of the dogs died. Mariska and her siblings survived — and were left to grow up without their mother.

My Mom Jayne doesn’t just revisit that tragedy — it reclaims the legacy of a woman who was more than just a blonde bombshell, and gives her daughter a platform to finally speak her truth.

The film screens at Carnegie Hall on Friday, June 13, at 7 p.m., followed by a conversation between Hargitay and actor-director Griffin Dunne.