Jennifer Lopez had been warned about sharing too much about her romance with Ben Affleck following their reconciliation nearly 20 years after their first split, according to a report.

Lopez, 54, and Fonda, 86, developed a tight bond after starring in the 2005 comedy-romance movie "Monster-in-Law." Lopez reportedly approached the latter to appear in her film dedicated to her husband, but Fonda raised some concerns about Lopez sharing details of her romantic life on screen. Fonda warned the "Marry Me" actress about how baring it all might affect them negatively, and her warning has recently resurfaced.

"First of all, I want you to know that I don't entirely know why, but I feel invested in you and Ben and I really, really want this to work," Fonda told Lopez in a phone call featured in Lopez's "The Greatest Love Story Never Told," the Daily Mail reported.

RELATED: Jennifer Lopez Reconnects With BFF Who Warned Her That Ben Affleck Is 'Not Fully Committed As A Partner': Report

Jennifer Lopez and Jane Fonda
Jane Fonda and Jennifer Lopez on stage at UCLA Longevity Center's 20th Anniversary ICON Awards on June 4, 2011 in Beverly Hills, California.
(Photo : Jerod Harris/Getty Images)

"However, this is my concern. Like it feels too much like you're trying to prove something instead of just living it. Every other photograph is the two of you kissing, the two of you hugging."

Lopez responded with a smile and laughed on-screen while saying, "That's just us living our life," per Variety.

Fonda agreed to appear in Lopez's film. However, she raised another concern after Affleck's "unhappy" look at the 2023 Grammys. But Lopez assured her that her husband was OK.

"Nothing! He was like, 'I've become the symbol of the beleaguered man,'" Lopez told her.

In the documentary, Lopez shared Affleck's love letters for her. He was reportedly taken aback at the sight of Lopez sharing the personal stuff with her guests.

RELATED: Ben Affleck May Not Be As 'Invested' In Jennifer Lopez Marriage, Wants To Prioritize Kids With Jennifer Garner: Relationship Expert

Jennifer Lopez and Jane Fonda
Jennifer Lopez and Jane Fonda pose backstage at UCLA Longevity Center's 20th Anniversary ICON Awards on June 4, 2011 in Beverly Hills, California.
(Photo : Jerod Harris/Getty Images)

"I did really find the beauty and the poetry and the irony in the fact that it's the greatest love story never told. If you're making a record about it, that seems kind of like telling it," Affleck told the cameras.

Meanwhile, Lopez admitted her husband was hesitant about her decision to tell their love story in a film or music. However, she was confident he would support her because he loved her.

"I don't think [Ben] is very comfortable with me doing all of this," Lopez admitted in the documentary. "But he loves me, he knows I'm an artist, and he's gonna support me in every way he can because he knows you can't stop me from making the music I made... he doesn't want to stop me. But that doesn't mean he's comfortable being the muse."

Lopez invested time and money in the project. Her longtime producer and partner, Elaine Goldsmith-Thomas, admitted that she was surprised when Lopez decided to put $20 million of her own money into the project after a potential partner pulled out.

Jennifer Lopez and Jane Fonda
Actors Jane Fonda (L) and Jennifer Lopez pose at the afterparty for the premiere of New Line Cinema's "Monster-In-Law" at the Armand Hammer Museum on April 29, 2005 in Los Angeles, California.
(Photo : Kevin Winter/Getty Images)

"'What are you doing?' I was worried. 'Why are you sharing your story? It's too personal. Stop it.' It made me uncomfortable for her," Goldsmith-Thomas said.

Despite the warnings, Lopez went on with the project. Months after it was released, her marriage with Affleck was plagued with rumors that they could be heading for divorce. They are already living in separate homes and have since put their $60 million marital mansion up for sale. However, they haven't addressed the divorce speculations.