Jesse Eisenberg was inspired to make A Real Pain after seeing online advert

Jesse Eisenberg came up with the idea for his movie A Real Pain after seeing an online ad.

The comedy-drama, which Eisenberg wrote and directed, stars the Zombieland actor and Succession's Kieran Culkin as Jewish cousins who go on a tour through Poland to honour their late grandmother and learn more about their family history.

Eisenberg was originally working on a story set in Mongolia when he came across an advert for concentration camp tours in Poland.

"It said: 'Auschwitz tours - with lunch.' It's such a weird idea, this tourism of tragedy," he said in a Q&A during Poland's American Film Festival, reports Variety. "When I saw that, I threw out my Mongolia script and looked at the photos from my first visit to Poland in 2008. I realised this was the story."

During his trip, The Social Network star wasn't able to emotionally connect with the trauma of what his Jewish ancestors faced in Poland during World War II. He used this experience to inspire how his A Real Pain characters felt during their organised tour.

"I remember feeling: 'There's nothing I can do to make myself connected to this trauma.' What am I supposed to do? Cut my arm?" he explained. "There's nothing you can do to feel what people felt in (concentration camp) Majdanek. I was standing in front of my family's house, not having any kind of catharsis. I didn't belong there anymore. I wanted them (his characters) to have the same feeling."

A Real Pain, which is already showing in U.S. cinemas, will be released in the U.K. on 10 January.