For 'A Real Pain,' Jesse Eisenberg learned to embrace the chaos of Kieran Culkin. Magic ensued

Jesse Eisenberg did not know Kieran Culkin was about to drop out of his movie.

It was just a few weeks before shooting was about to begin on “A Real Pain,” and Eisenberg and much of the crew were already in Poland preparing. The film, which opens in theaters Friday, is deeply personal for Eisenberg, who at age 17 started connecting more with his own Polish heritage through his aunt.

The story, rattling in his mind for almost two decades, follows two cousins on a Holocaust tour after the death of their grandmother. It’s about modern pain and historical trauma — serious themes handled with the light, humorous touch of an odd-couple road trip film. One of them, David, is a little uptight, a little neurotic. The other, Benji, is a little more chaotic. You can guess which one Culkin had agreed to play.

“I connected with the character right away,” Culkin said. “I knew I wanted to do it. Like, creatively, I wanted to be a part of this thing.”