Mariska Hargitay is paying tribute to her former “Law & Order: Special Victims Unit” co-star Richard Belzer, who died at the age of 78 Sunday.

“What a heart and soul,” she told Savannah Guthrie on “Today” Thursday. “He was family and taught me so much about taking risks and creativity and trust, and he brought so much joy to the set.”

Hargitay described Belzer as an “acerbic, quick-witted, brilliant mind.”

“He was just such a beautiful and complex” person, she added. “It was such a privilege to know him.”

Belzer died peacefully at his home with his family in Beaulieu-sur-Mer, in southern France, his longtime friend Bill Scheft confirmed to USA TODAY. Scheft, a writer who had been working on a documentary about Belzer, told The Associated Press there was no known cause of death, but that Belzer had been dealing with circulatory and respiratory issues.

Belzer’s “Law & Order” co-star Chris Meloni shared a photo on Twitter kissing the late star on the cheek. “Good bye mon ami. I love you,” Meloni wrote alongside the tribute. He also posted a photo of Hargitay feeding Belzer an apple.

In addition to his work as a comedian, Belzer played the role of Detective John Munch for 23 years. The character first appeared in NBC’s “Homicide: Life on the Street” in 1993 and made its way into several other unrelated shows including, “Law & Order: Special Victims Unit,” “Law & Order: Trial by Jury,” “30 Rock,” “The X-Files,” “Arrested Development,” “The Wire” and “Unbreakable Kimmy Schmidt.”

Belzer never auditioned for the role of Detective John Munch. After hearing him on “The Howard Stern Show,” executive producer Barry Levinson brought Belzer in to read for the part.

“I would never be a detective. But if I were, that’s how I’d be,” Belzer once said. “They write to all my paranoia and anti-establishment dissidence and conspiracy theories. So it’s been a lot of fun for me. A dream, really.”