Photo: Victoria Stevens

Laura Dern & Diane Ladd

Diagnosed four years ago with a lung disease called idiopathic pulmonary fibrosis, Ladd, now 87, began going on walks around Santa Monica with her daughter to try and strengthen her breathing. Their discussions as they walked — including everything from their own journeys as actors to grief and heartbreak in their lives —“grew into a profound deepening of our relationship,” Dern tells PEOPLE in this week’s issue.

It also opened a can of worms.

Victoria Stevens

Laura Dern & Diane Ladd

“You made Ellery embarrassed,” Dern wrote to Ladd. “Thinking that boys can’t have long hair is just so outdated.”

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Ellery Harper, Jaya Harper, Diane Ladd, and Laura Dern attend the 92nd Annual Academy Awards at Hollywood and Highland on February 09, 2020

Afterward, she left Dern’s house “in a huff” parked the car, and sobbed. “You treated Grandmother wrong,” she wrote. “I would have never treated my mother that way if she’d cut your hair. And she did cut your hair! Many times! I didn’t always love the haircuts, but so what? I loved her.”

Dern recalls being “devastated. It wasn’t just the haircut; it was that you said he looked like a girl,” she wrote. Ladd insists she never said that to her grandson, only to Dern.

In the book, Ladd allows that the incident still bothers them both. “Did Ellery want it cut? Or did he just know I wanted him to cut it?” she wrote. “All you can do is hash it out and know where you stand and agree to disagree.”

After Ladd revealed to PEOPLE that one of her proudest moments of Dern was when she gave birth to her kids, Dern had an addendum: “That’s so beautiful, Mom. I just want to add, if I may, because I was so moved, that you said when your child gives you a child. That doesn’t mean you get to cut its hair!”

Laura Dern & Diane Ladd - Honey, Baby, Mine book jacket

“A mother’s wisdom understands that that’s what the child wants,” Ladd responded. “Here we go.”

“In every interview, I get to reiterate how wrong you were about cutting my son’s hair!” added Dern, laughing. “This book wassoworth it.”

source: people.com