New Kid Quits Mid-Show (Video)

New Kid Jonathan Knight walked off stage during his band's iHeartRadio concert on Thursday night.

New Kid quits mid-show (Photo: Twitter)

New Kids On The Block were midway through their show at the iHeartRadio Theater in New York City when suddenly Knight exited without explanation, leaving his band members and audience confused.

Knight was spotted using his cell phone to the side of the stage in the beginning, before leaving the stage when he was just about to do his solo in the ballad "Survive You." Despite the audience chanting for him to return, he never did.

Later that night, Knight posted a tweet saying, "I'm sorry," but he did not explain why he left.

The singer has history of anxiety and panic attacks, which he opened up in his past interview with Oprah Winfrey.

"The whole New Kids thing was crazy," he told Winfrey in 2011. "The more it grew, the more I just felt like I was trapped. I just always had this feeling inside me of always being nervous and afraid of situations."

Meanwhile, two years after New Kids united with Backstreet Boys for the co-headlined NKOTBSB tour, the '90s boy band will join Boyz II Men and the recently reunited 98 Degrees for this summer's "The Package" tour, kicking off on May 28 in Uncasville, Conn.