EXCLUSIVE: Penny Marshall Opens Up About Late Brother Garry Marshall: 'He Gave Me a Life'

ET was on the set of the upcoming Odd Couple tribute to Garry Marshall, where his sister, Penny Marshall, revealed just how much he meant to her.

ET was on the set of the upcoming Odd Couple tribute to Garry Marshall, where his sister, Penny Marshall, revealed just how much he meant to her.

"My brother gave me a life," Penny told her nephew, Scott -- Garry's director son -- who was interviewing her for ET. "It's not many people who have a brother who give them a life. He gave me a life and I appreciate it and I tried to not let him down."

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Penny's career was just one of many that Garry launched in his five-decade-long career. As the mastermind behind such beloved TV shows and movies such as Happy Days, Mork & Mindy, Pretty Woman and The Princess Diaries (to name just a few!), Garry greatly impacted the careers of stars like Julia Roberts, Robin Williams, Anne Hathaway, Kate Hudson, Henry Winkler, Rob Lowe, John Stamos, Scott Baio and Mayim Bialik.

The legendary director, producer and creator gave his younger sister her first big break as Jack Klugman's secretary on The Odd Couple, then lightning struck when Garry cast Penny as Laverne DeFazio on Happy Days in 1975. Her character, along with Cindy Williams' Shirley Feeney, was so popular it earned a spinoff the following year, which lasted eight seasons.

Williams is also featured in The Odd Couple tribute episode, and she told ET's Nischelle Turner how she found out about Garry's death.

"Penny called me," Williams recalled. "She said, 'Garry's sick. I think he's dying.' I didn't believe her. I thought it was a joke. That night he passed, and someone brought me this picture of Penny, me and Garry and Henry. It was at the Hollywood Walk of Fame ceremony and I just burst out crying."

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Thomas Lennon, who plays Felix Unger in the current Odd Couple on CBS, admitted he was also devastated by Garry's loss.

"If you could go back somehow and tell the childhood version of myself that the creator of Happy Days and Laverne & Shirley would be my friend, I would never have believed it. Excuse me," Lennon said through tears. "I am Irish. I cry a ton," he joked.

Garry brought the original Odd Couple to TV in the '70s and he stole the show as Matthew Perry's dad, Walter, in the CBS reboot. Perry told us Garry was an invaluable asset on set.

WATCH: Stars Share Touching Tributes to Celebrated Director Garry Marshall

"He was always around pitching jokes at every table read," Perry said. "He helped design the sets. He said, 'Put a peephole on the door. Peepholes are funny.' And so we put a peephole on the door. We just listened to everything he said."

The tribute episode, airing Nov. 7, follows Oscar (Perry) as he reconnects with people from his father Walter's life while preparing to scatter his ashes behind the candy factory his father used to own.

In addition to Penny and Williams, Ron Howard, Marion Ross, Anson Williams, Don Most and Pam Dawber will also guest star on the episode.