Jennifer Garner Says Mark Ruffalo Almost 'Dropped Out' of 13 Going on 30 Over Difficult Dance Rehearsals

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Mark Ruffalo almost couldn't hang with his 13 Going on 30 costars.

The actor starred in the beloved 2004 comedy alongside Jennifer Garner and Judy Greer as the adult versions of their teenage characters. In one memorable scene, all three perfectly dance the iconic choreography to Michael Jackson's "Thriller," a song that was all the rage when their characters were young.

But Garner jokes that scene was almost Ruffalo's breaking point during the making of the hit film.

"We started to learn the dance. Our first rehearsal, I think it was Mark and Judy and me, and Judy and I were both dancers growing up and poor Mark didn't know that. And he came in and he hated the rehearsal process so much he almost dropped out," Garner says in a video for The Skimm, laughing at the end as she remembers what a hard time Ruffalo had with the choreography.

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Ruffalo, 53, responded to Garner's remarks under PEOPLE's Instagram post.

"It didn't help that it took me 3 hours to learn what Jen mastered in about about 20 minutes!" he joked.

Of his character Matt Flamhaff, Ruffalo said, "Matty had to be dragged out on that dance floor as well, poor guy. But all this time later he is grateful he did!"

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Garner recently reunited with Ruffalo for their first movie together since 13 Going on 30. The two play a married couple and parents to Ryan Reynolds' character Adam in The Adam Project. The upcoming film sees Reynolds play a person who goes back in time to find his dad, played by Ruffalo, and save the world.

Garner, 48, told Good Morning America that it was easy to get back in the rhythm with Ruffalo.

"It was wonderful," she said of working with Ruffalo 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."

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

"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?"