Robert Wagner, 96, took to Instagram on Monday to wish his "Hart to Hart" co-star Stefanie Powers a happy 84th birthday. Powers, who played Wagner's wife Jennifer Hart on the series, received a warm message from the actor.

"Happy Birthday, Mrs. H!" Wagner posted. "Wishing my favorite partner in crime-solving a fabulous birthday! Some things never go out of style… especially you!"

Wagner and Powers starred as the wealthy sleuthing couple Jonathan and Jennifer Hart in the television series "Hart to Hart," which ran for five seasons from 1979 to 1984. They reprised their roles in two subsequent television films. Powers recalled to People that Wagner had recommended her for the show after they worked together on his previous series, "It Takes a Thief." She described their on-screen chemistry as "lucky" and stated that she and Wagner "talk to each other quite often," considering him like a brother.

Wagner's birthday tribute comes as this month marks the 45th anniversary of the death of his late wife, Natalie Wood. The actress died at age 43 on November 29, 1981, near Santa Catalina Island, California, in what authorities initially ruled an accidental drowning. Wood's death occurred while she was on a boat trip aboard Wagner's yacht, the Splendour, with Christopher Walken and the boat's captain, Dennis Davern, also present.

In 2011, Davern provided details about a conflict between Wood and Wagner prior to her death, prompting authorities to re-open the investigation. In 2018, Wagner was named a "person of interest" in the case. However, the Los Angeles County Sheriff's Department stated in May 2022 that all leads in the case had been exhausted and that it remained an open, unsolved investigation. They also confirmed Wagner had been cleared of involvement.

Wagner portrayed Jonathan Hart to Powers' Jennifer Hart over five seasons of the series spanning 1979-1984. Pictured 1981

Wood's daughter, Natasha Gregson Wagner, who was adopted by Wagner, has spoken out in defense of her stepfather. She told Vanity Fair in October that it was "absurd" for him to be "maligned" and stated her belief that her stepfather would have done anything to protect her mother. She added that she did not want his legacy to be tarnished by "mistruths or untruths."

Wagner took to social media as this month marks the 45th anniversary of the mysterious death of his late wife Natalie Wood. Pictured 1972