On the evening of April 7, 1970, the 25-year-old actress, with just two film credits to her name, was half a world away from the Dorothy Chandler Pavilion in Los Angeles when Fred Astaire opened an envelope and read her name as the best supporting actress winner for Cactus Flower.

Instead of basking in the glow of television history, the “Laugh-In” star was sound asleep in London as an early call time loomed for her next film, “There’s a Girl in My Soup,” opposite Peter Sellers.

Hawn, now 77, is sitting in front of a fire in a woodpaneled study in her Pacific Palisades home as she recalls those few seconds that changed the trajectory of her life but that she never experienced firsthand. Throughout her trailblazing career, which includes such classics as “Foul Play,” “Private Benjamin,” “Overboard” and “The First Wives Club,” Hawn has created no shortage of indelible characters and experienced many artistic triumphs. But if she could get one do-over, she would haul her ass to that 1970 ceremony.

Part of the problem, Hawn admits, is that she didn’t expect to win. After all, this was long before Oscar prognosticating, handicapping and lobbying became de rigueur. “Cactus Flower” was her first real movie role (notwithstanding her bit part in the Disney musical “The One and Only, Genuine, Original Family Band”), and she was nominated alongside accomplished actresses like Sylvia Miles for “Midnight Cowboy” and Susannah York for “They Shoot Horses, Don’t They?” Unlike the 63.1 million who tuned in live in the U.S., Hawn missed the show.

“I forgot it was on television that night,” she says. “Then I woke up to a phone call at like 4 in the morning. And it was a man’s voice and he said, ‘Hey, congratulations, you got it.’ ‘I got what?’ ‘You got the Academy Award for best supporting actress.’” Hawn thanked the disembodied voice, hung up, called her parents and “had a good cry.”

Though Raquel Welch accepted the coveted statuette on Hawn’s behalf that night, Hawn never watched footage of the moment until just a few weeks ago, while traveling with this year’s Oscar host, Jimmy Kimmel, to a mutual friend’s party. “He said, ‘Did you ever see the part where you’re being announced by Fred Astaire?’ And I said, ‘Fred Astaire?!’ He’s my idol. And I didn’t know he was the one that announced my name. I got emotional when I finally saw it.

While Hawn wasn’t in the room that night, she certainly made her way back to the Academy Awards, as a return nominee in 1981 for “Private Benjamin,” as a co-host in 1987 (alongside Chevy Chase and Paul Hogan), and 13 times as a presenter, most notably for another no-show winner, George C. Scott. In 1971, the “Patton” star boycotted the Oscars because he was ideologically opposed to actors being pitted against one another in a contest. “I was amused and shocked,” she says of that moment, which could have been awkward but was defused by Hawn’s “Oh, my God!” and trademark giggle.

To this day, people believe their banter was real. Russell says it was not.