Mariska Hargitay is sharing a family secret -- she is not biologically a Hargitay.

The 61-year-old revealed her late dad Mickey Hargitay, who raised her after her mom Jayne Mansfield died in a 1967 car accident that the Law & Order: SVU actress survived as a child, is not her biological father. That would be Brazilian-born Italian singer Nelson Sardelli, 90. When Mariska was 30, she watched him perform in Atlantic City and then introduced herself. In character.

"I went full Olivia Benson on him," she told Vanity Fair in an interview published May 17, adding. "I was like, 'I don't want anything, I don't need anything from you...I have a dad.'"

Nelson, she said, burst into tears upon meeting her, telling her, "I've been waiting 30 years for this moment."

In 1962, Jayne filed for divorce from the Hungarian-born actor -- her costar in films such as The Loves of Hercules -- and later become romantically involved with Nelson. She and Mickey reconciled before Mariska was born in 1964, Vanity Fair reported, but finalized their divorce later that year.