Jane Fonda Jokes About Why She and Her 80 For Brady Costars Were a 'Problem for the Director'

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Sometimes casts just have a lot of chemistry!

That can be said for Jane Fonda and her 80 for Brady costars Sally Field, Rita Moreno, and Lily Tomlin, who she joked became a "problem for the director."

"Getting us to stop talking to each other and start playing our characters," Fonda, 85, joked to PEOPLE of their fun on set. "You know, we just — whether it was Rita and I singing — she starts a song and I finish it and vice versa. And I don't know, we just, we really enjoyed it."

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The movie, directed by Kyle Marvin, premiered Friday at the 34th Annual Palm Springs International Film Festival, where Fonda opened up with PEOPLE about the decades of experience she had building chemistry with — and being a fan of — her fellow actresses in the film.

"You know, I've known Lily for 50 years," she says. "I've made three other movies with her and another one is being shown on Sunday, by the way. Moving On, which I love, dark comedy. I've known Sally 40 years, and I just so admire her and watching her process of creating the character during the course of filming was really special."

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Moreno, 91, adds that mending their skills for 80 for Brady was "like nothing else," calling her costars "spectacularly special actresses."

"So, you know, when the names were first mentioned to me, I said, 'Who?! Who did you say is in this?! Oh, my God, that's incredible.' And you know, it was incredible. It was fabulous," Moreno says of the lineup.

"This woman who is next to us here, Jane Fonda, is sensational and funny. And the movie, I'm happy to say, it's so wonderful to sit here and not be even a little bit nervous. It's funny, it does everything it's supposed to do, this movie. And this woman is — I keep saying 'This woman' because she's right next to me and you can't see her — but Jane is just spectacular, and she's funny."

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The movie itself, which hits theaters on Feb. 3, follows the starring four as NFL fans who venture to Houston for 2017's Super Bowl LI, the year quarterback Brady (who now plays for Tampa Bay) led the New England Patriots to a victory over the Atlanta Falcons. The film's trailer shows them on a mission to get into Super Bowl LI, as they attend a food-eating competition hosted by Guy Fieri and even dance with Billy Porter to get their way in.

80 for Brady also stars Bob Balaban, Glynn Turman, Ron Funches, Jimmy O. Yang and Harry Hamlin. The NFL superstar Brady appears as himself and serves as a producer of the movie.

When asked what she took away from her costars, Moreno tells PEOPLE that she learned "how professional" they all were. "There's no joking about this. They're not — they haven't been around all this time for nothing," she says. "And they are immensely talented. I think Sally's incredible, actually. She's a great dramatic actress. But then again, so is Jane Fonda. I mean, those movies that she's made, you know."

While Tomlin says her biggest lesson of the experience was to "keep pitching and take every job like that that you can," Fonda says Moreno taught her something, too. "I mean, when I started to feel tired, I'm 85, but she's 91, and she never got tired," Fonda says. "She was so full of energy and imagination and joy. I mean, look at her. I just, you know, I'm in awe of her, and she's my new role model."

As for seeing all the magic firsthand, Hamlin describes what it was like to witness the four "titans of the industry" join forces for the Brady-focused film.

"You know, there was no clashing going on at this point but... to work with these people, I mean, are you kidding me? I have no words really to describe it," he tells PEOPLE. "But you know, how comfortable does one feel when one is working with the ultimate professionals, and they're so gracious and so inviting, and so lovely to work with."