Mark Ruffalo Says It Was 'Amazing' to Reunite with Jennifer Garner: 'Picked Up Where We Left Off'

Mark Ruffalo opened up to PEOPLE (The TV Show!) Monday about reuniting with his 13 Going on 30 costar Jennifer Garner for The Adam Project, out March 11

Jenna and Matty forever!

Mark Ruffalo and Jennifer Garner star in Netflix's upcoming sci-fi action flick The Adam Project, reuniting the two actors onscreen almost two decades after they starred as love interests in 2004's 13 Going on 30.

At Monday's world premiere of The Adam Project in New York City, Ruffalo, 54, told PEOPLE (The TV Show!)'s Segun Oduolowu that working with Garner, 49, again was nothing short of "amazing."

"It was like we picked up where we left off," he said. Joking of his and Garner's onscreen son in The Adam Project, he added, "It was like Jenna and Matty went off and had Ryan Reynolds as a kid, and no one can understand how he got so tall."

Added Garner of Ruffalo, "I know he was excited to be with me and I was too. We had a great time."

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Reynolds, 45, plays a futuristic time-traveling pilot in The Adam Project — one who crash-lands in 2022 and interacts with his 12-year-old self, ultimately teaming up to save the future and his (their?) wife, Zoe Saldana. Newcomer Walker Scobell stands in as Reynolds' younger self, while Garner and Ruffalo play Adam's parents.

Mark Ruffalo and Jennifer Garner. Mark Ruffalo/instagram

"It was my wife who suggested Jen Garner to play the mom," director Shawn Levy recently told PEOPLE. "I shared the idea with [Ryan] and he loved it. He then, after the fact, pointed out to me that this was the 13 Going on 30 reunion."

"So even though it looks like the smartest marketing move ever, it was strangely accidental, but we got all the benefit of the chemistry that exists between Mark and Jen," continued Levy, 53.

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Added Reynolds of Ruffalo and Garner sharing the screen once again, "They really had a beautiful — and still do — just a sheer chemistry that you can't create, it's just there."

"To reunite them in a different kind of time-travel movie, but one that's just as sweet and warm-hearted felt really... we just felt very lucky," said Levy.

Garner said on Good Morning America last year that it was easy to get back in the rhythm with Ruffalo.

"It was wonderful," she said of working with him again. "We were playing a married couple and we just had this instant comfort and obviously there's just such a connection and a warmth. It was actually a really beautiful experience to revisit that relationship."

As for her 13 Going on 30 character Jenna Rink, the actress said she hoped she would "still be whimsical and have a little bit of fun" nowadays.

"She would have to still have some 13-year-old in her," Garner said. "But, oh, gosh, I have to go back and watch this movie. It's so fun ... Is Poise still going? Is it all online? What's happening?"

The Adam Project debuts on Netflix March 11.