“Lauren Graham EXPOSES Private Letter from Hollywood Legend Diane Keaton — ‘Her Words SHATTERED Me in the Best Way!’ Shocking Revelation About Gilmore Girls Star’s Secret Bond with Her Iconic On-Screen Mom Will Leave You in Tears!”

Keaton died on Saturday, Oct. 11, at the age of 79

Lauren Graham in January (left); Diane Keaton in September 2023 (right).Credit : Manny Carabel/Getty; Paul Morigi/Getty

Graham, 58, shared a sweet Instagram post with a photo of a letter Keaton sent her. The actresses starred together in the 2007 film Because I Said So. In the film Keaton played Daphne, an overbearing mother of three girls: Milly (Mandy Moore), Mae (Piper Perabo) and Maggie (Graham).

In the letter, Keaton wrote, “Please don’t be a stranger. Please invite me to one of your dinners. And finally. . . . Please hug yourself in the morning, and remember to write your book, and don’t let yourself get anxious, you big winner, you.” Keaton signed it, “Love, Di.”

The Gilmore Girls alum explained in the caption, “A few lines from a letter Diane Keaton wrote me years ago, when writing a book was just a dream of mine. Her work as an actor was an inspiration to me. Her encouragement changed my life.”

From left: Mandy Moore, Lauren Graham, Diane Keaton and Piper Perabo in ‘Because I Said So’.Suzanne Tenner/Universal/Kobal/Shutterstock

Moore, 41, also paid tribute to Keaton in an Oct. 11 post. Alongside a photo of them snuggled on the couch in the movie, she wrote, “They say don’t meet your heros but I got to work with one of mine and even call her ‘mom’ for a few months. An honor of a lifetime.”

She continued, “What an incandescent human Di is and was. I am so sad she’s gone for all the reasons but also because it felt like she’d be here forever, dazzling us with her talent and charm (and her style, c’mon)!!! One of the very best to ever do it. All my love to her children and loved ones.”

Keaton’s early career included both her role as Kay, the wife of Al Pacino’s Michael Corleone, in The Godfather films and her Oscar-winning turn as the title character in Annie Hall. In the late 1980s, she began appearing more regularly in comedies and romantic comedies, including her collaborations with Nancy Meyers like 1987’s Baby Boom, 1991’s Father of the Bride and 2003’s Something’s Gotta Give and 1996’s The First Wives Club. She also played family matriarchs in 2005’s The Family Stone and 2015’s Love the Coopers. More recent roles included 2018’s Book Club and 2023’s Book Club: The Next Chapter.

Diane Keaton in October 2022.Michael Buckner/WWD via Getty

Kimberly Williams-Paisley, who played Keaton’s daughter in the Father of the Bride series, told PEOPLE on Saturday, “It’s really one of the best memories I’ll ever have in my life, getting to work with Diane.”

“She had such a great sense of humor, and was just full of laughter, and so generous with compliments,” she said. “I remember after we did Father of the Bride (3)ish [in 2020], she asked for everyone’s phone number and then she called every single person that worked on it and just told them what a great job they did. She was just very giving like that.”

But if others thought Keaton was a good mentor, she didn’t agree. Asked by PEOPLE in 2019 about the wisdom she’d gained in her then-73 years, she said, “I don’t know anything, and I haven’t learned. Getting older hasn’t made me wiser.”

She added, “Without acting, I would have been a misfit.”