Tony Bennett has canceled his highly-anticipated London concert after reportedly collapsing during a rehearsal for the performance earlier today.

“Unfortunately, Tony Bennett has come down with a flu virus which has prevented him from performing the second of two sold-out shows in London,” the 88-year-old singer’s rep said in a statement.

tony bennett

Tony and Lady Gaga performing in February 2015.

Tony and Lady Gaga, 29, had a scheduled concert at London’s Royal Albert Hall tonight as part of their Cheek to Cheek tour. The duo previously performed at the venue on Monday evening, where they posed for photos with Prince Harry, 30, backstage.

RELATED: See Tony Bennett & Lady Gaga and 5 More Duets at the Grammy Awards!

“We were getting ready to take our seats and literally just 10 minutes before we were told it was canceled,” concertgoer Rory Emery told Closer. “They told us he’d been taken ill.”

tony bennett

Tony, Lady Gaga and Prince Harry on Monday, June 8.

“We just left. No one’s really there. Everyone’s angry and just left. It’s a shame but there’s nothing we can do about it,” Emery added to Closer.

“Sorry to not be singing in London tonight. I love my fans in the UK and appreciate all the well wishes to get over this flu quickly,” a tweet published to Tony’s official Twitter account on the afternoon of Tuesday, June 9 read.

This story is still developing…