Talk about a power lunch.

Bono joined Barack and Michelle Obama at Stephen Starr’s restaurant Upland on Friday, and the trio caused quite the stir.

“Everyone in the restaurant knew they were there,” a source told Page Six of patrons who were tipped off by “tons” of Secret Service in the Gramercy eatery. “There was a major buzz in the air.”

The former first couple and the U2 frontman ate in a private dining room downstairs for a “casual lunch” — with no way of avoiding crowds, as they had to walk though the main dining area to get to their table. Bono and the former president entered first and Michelle followed behind.

We’re told Barack Obama “flashed his million-dollar smile” as he waved to the crowd while exiting the restaurant. Fans also cheered for the famous diners.

Meanwhile, on Thursday night Obama made a surprise appearance at Carbone during a D’Ussé Dinner Series event, when, “in the middle of the dinner, Secret Service started surveying the area,” a source told Page Six.

“They were notifying the group that President Obama was coming to dine at Carbone shortly.” When Obama arrived, the group greeted him as he made his way to a private room at the restaurant to enjoy his own plate of spicy rigatoni.”

Hosts at the event included Roc Nation Latin CEO Romeo Santos.