Ed Sheeran has slammed the Backstreet Boys for playing new music at their reunion shows.

The 23-year-old English singer-songwriter seems to know some of the 90s boyband’s biggest hits, and he thinks BSB are letting fans down with unrecognisable tunes on their set list.

“I study how other people perform and that is unacceptable, as the Backstreet Boys have so many hits,” he lamented to UK newspaper The Sun.

The Sun reports Ed was particularly upset upon hearing Backstreet frontman Brian Littrell played an acoustic set to open the band’s show.

“No mate — do that if you have your own gig, Brian. I played the Royal Albert Hall and did two new songs, but I know that’s what people want. The Backstreet Boys, what are they doing? Play your hits,” he said.

The singer says there are few cases where that might be acceptable. But Brian and his bandmates A,J. McLean, Howie Dorough, Nick Carter and Kevin Richardson don’t fall into that prestigious category.

“If you’re a proper muso and people go to your gigs to witness your musicianship, à la Eric Clapton and Stevie Ray Vaughan, do it.

“But if you’re a pop star play your pop songs," he ordered.

Ed also gave numerous examples of successful pop stars who give audiences what they want – and that’s usually not new tracks.

He gave props to Justin Timberlake and Sir Paul McCartney for being masterful at pleasing fans.

“I love the Backstreet Boys, and I would not want to go to a gig and not hear all the hits, that would really annoy me. Like when I saw Justin Timberlake, it was one of the best shows I ever watched as it was back-to-back hits, people need to do that much more,” he explained.

“I went to see Paul McCartney and I knew every song, hit after hit.”

The Backstreet Boys have been on their 20th Anniversary Tour since last spring.

The band is scheduled to launch the North American leg of the tour May 3, followed by another European leg in June. The shows are scheduled to wrap in Gdansk, Poland on July 27.