The 70-year-old actor was filming The Intern in the Cobble Hill neighborhood, but didn't want to miss USA-Germany World Cup game.
A local resident told Business Insider that a member of De Niro's crew contacted him in an email, at first asking for access to his rooftop.
"Our lead actor, Robert De Niro, would very much like to watch the World Cup game, today at 12p," read the message. "Would it be possible to place a small portable satellite on the building rooftop ASAP and run a cable to the street to help facilitate this request?"
But De Niro managed to find a stranger who invited him to watch the game at his house.
"We got another email from a neighbor saying he talked to the crew and apparently he found a house of people watching it and joined them."
De Niro said back in January that he's "not into" soccer, but he must have come round for the World Cup.
"He wasn't going to miss the game!" a source told Us Weekly. "He's a true American. He has no problem hanging, he enjoyed it."