Jane Fonda isn’t one to mince words — even when it comes to Jennifer Lopez.

The outspoken Oscar winner recently appeared in “The Greatest Love Story Never Told,” a documentary about Lopez making her latest album, “This Is Me…Now,” and its accompanying music film.

Fonda shared “concern” about Lopez’s rekindled relationship with Ben Affleck.

The newlyweds famously dated previously in the early 2000s, but endured so much tabloid fodder and attention that “Bennifer” broke off their engagement in 2004. Fonda, who starred opposite Lopez in “Monster-in-Law” (2005), is now worried about a potential repeat.

“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, really want this to work,” she tells Lopez over the phone in a scene from the documentary, which premiered Tuesday on Prime Video.

“However, this is my concern,” Fonda says. “Like, it feels too much like you’re trying to prove something instead of just living it. You know, every other photograph is the two of you kissing, the two of you hugging.”

While Lopez argues they’re just “living our life,” the film does probe their contrasting views on the spotlight. It reveals Affleck gifted her a book for Christmas in 2021 of every letter and email they ever exchanged, only for Lopez to reportedly share them with others.

Affleck had titled the book, “The Greatest Love Story Never Told,” inspiring the name of the film.

“I had a very firm sense of boundaries initially around the press, while Jen I don’t think objected to it in the way I did,” he says in the film. “I very much did object to it. Getting back together, I said, ‘Listen, one of the things I don’t want is a relationship on social media.’”

“Then I sort of realized it’s not a fair thing to ask,” Affleck continues. “It’s sort of like, you’re gonna marry a boat captain and you go, ‘Well, I don’t like the water.’ We’re just two people with different kinds of approaches trying to learn to compromise.”

Lopez, who recently clarified what caused their first relationship to falter, rekindled their romance in April 2021. The couple got engaged one year later and eloped in July 2022, but held a more traditional wedding in Georgia at the end of that summer.

Lopez explained in a new Apple Music interview with Zane Lowe that “it didn’t feel like we were going to make it” the first time around — and they simply weren’t “mature” enough at the time.

“I don’t think [Ben] is very comfortable with me doing all of this,” Lopez says in the film, of her projects. “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.”

She adds: “But that doesn’t mean he’s comfortable being the muse.”