The scenes shot inside the Anne Frank House were actually filmed in Pittsburgh on a stage.
"Our wonderful production designer, Molly Hughes, built a giant replica of the interior of the Anne Frank House on the stage in Pittsburg because you can’t shoot in the historic section of the Anne Frank House. It looked exactly like it," he says.
The cast was always laughing, even in between emotional scenes.
"We were literally laughing all the time and all our off-set time was spent laughing. Even on days when everybody was crying during scenes, we were laughing in between takes and just having a good time," he says.
John Green was extremely emotional throughout the entire filming process.
"The day I start shooting my editors are starting to do rough edits. So while we’re on set shooting I’ll be looking at scenes every day as they’re cut and sending the editors notes. There were many times we brought John in to watch and he’d cry or he’d be sitting at the monitor watching the scene and I’d look over and he’d be crying," he says.