The actors and longtime friends previously starred together in 1999’s Analyze This and 2002’s Analyze That

Robert De Niro (L) and actor Billy Crystal attend Muhammad Ali's Celebrity Fight Night XX

Photo: Michael Buckner/Getty Images

Billy Crystal thinks Robert De Niro’s baby news is “wonderful.”

The actor, 75, chatted with PEOPLE at the screening of the Yogi Berra documentary It Ain’t Over at the Hard Rock Hotel New York on Wednesday night, where he reacted to longtime friend and former costar De Niro, 79, welcoming his seventh child.

“I was with him two weeks before the baby was born,” Crystal said. “You know, it’s amazing.”

Noting that De Niro and girlfriend Tiffany Chen “just love each other, and they want to do this together,” he added, “I think it’s a beautiful thing. It’s wonderful.”

De Niro has six children from previous relationships. He and his first wife, Diahnne Abbott, are parents to daughter Drena, 51, and son Raphael, 46. In 1995, he welcomed twin sons Julian and Aaron, 27, with his former girlfriend, model and actress Toukie Smith. De Niro also shares son Elliot, 24, and daughter Helen Grace, 11, with his ex-wife, Grace Hightower.

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Robert De Niro and Billy Crystal pose backstage at the hit musical "Mr. Saturday Night" on Broadway

Bruce Glikas/WireImage
Billy Crystal and Robert De Niro Reunite Backstage on Broadway, 20 Years After Analyze That

Earlier this week, De Niro revealed that he has seven kids when he was asked how his six children were doing in an interview with ET Canada.

“I just had a baby,” he shared, though he didn’t provide any further details about the newest family member or his partner.

His About My Father costar Kim Cattrall said he welcomed his seventh child with his rumored girlfriend Chen, however.

“God bless him, his significant other. Tiffany is such a beautiful woman,” Cattrall, 66, told Extra. “She came to the set once with her family and watched filming, and she was gorgeous and sweet. I’m happy for both of them.”

De Niro also shared wisdom about being a good father in a conversation with Access Hollywood this week.

“Sometimes I don’t think people really know what being a good father is, you know you have a responsibility, but it’s a mystery, it’s a lot of excitement but scary and you do your best,” he said.

RELATED VIDEO: Robert De Niro Reveals He ‘Just Had a Baby’ at 79, Now Is a Dad of 7

For Crystal, working on It Ain’t Over was a passion project “because it’s important.”

“[Yogi’s granddaughter] Lindsey needed to make this movie, and got it done in the way that she did that everyone wanted to be there for this man,” he told PEOPLE. “All the people who were in that felt it was an honor.”

It Ain’t Over hits theaters on May 12.