Hollywood star remembers Diane Keaton in emotional message

Reese Witherspoon couldn’t hold back tears as she paid tribute to her late friend and mentor, Diane Keaton.

The Morning Show star got emotional while speaking onstage at her media company Hello Sunshine’s Shine Away event in Los Angeles on Saturday, where she reflected on the lasting impact Keaton had on her life and career.

“Diane was really important, she was one of my first mentors in this business,” Witherspoon shared in a heartfelt video she later posted on Instagram.

She went on to recall their first encounter, explaining that she was just 15 years old when she auditioned for the Annie Hall star, who would go on to direct her in the 1991 television film Wildflower.

“That was only my second or third audition,” Witherspoon remembered, smiling through her tears. 

“She goes, ‘Who are you?’ And I said, ‘I’m Reese Witherspoon and I’m from Nashville, Tenn.’ And she said, ‘Are you making that up? That accent you’re doing?’”

Keaton ended up casting the young actress as Ellie Perkins, a teen who helps rescue an abused, partially deaf girl, played by Patricia Arquette. Looking back, Witherspoon said Keaton saw something in her that she didn’t yet see in herself.

“She was incredible,” Witherspoon said. “A truly unique person.”

As she wrapped up her tribute, Witherspoon encouraged fans to celebrate Keaton in their own way. 

“So for Diane, watch one of her movies and wear a really cool, interesting outfit, black and white,” she said. “Take a cool picture and just live your dream. Just be your unique, interesting self—I think Diane would be really happy.”

In her Instagram caption, Witherspoon added, “Diane Keaton changed the way we all saw women on screen – smart, funny, stylish, and completely original. I’m so grateful to have had her as a mentor.”

Keaton passed away in California at age 79. 

While she appeared happy and healthy in her final Instagram photo in April, smiling alongside her beloved dog Reggie, a close friend told PEOPLE that her health had taken a sudden and unexpected decline in the months before her death.