AceShowbiz - Singer/actor John Barrowman had to cancel a pair of weekend concerts to undergo spinal injections after suffering a "severe" neck injury.

The "Arrow" star took to social media early on Saturday, November 30 to announce that his doctors had ordered him to postpone that evening's show in Bristol, England, and another in Glasgow, Scotland on Sunday as they examined the issue.

"I'm devastated to have to tell you that due to a severe neck injury, which has made it impossible for me to sing & move, I've been rushed to hospital for a diagnosis," he posted on Instagram, admitting he was "so disappointed and upset" to miss the performances.

He subsequently revealed he had undergone an MRI (magnetic resonance imaging) scan, which helped medics pinpoint the cause of his pain as facet joint syndrome - an arthritis-like spinal condition, for which the 52-year-old was treated with anti-inflammatory "intraspinal injections".

Showing off a small bandage on his back, he wrote, "Procedure done. It was a bit uncomfortable."

Barrowman is hoping the shots will get him "back up & running again" by Monday, when he is still expected to hit the stage in Manchester, England for his "A Fabulous Christmas" tour.

He also took the opportunity to thank fans for their well wishes during his ordeal.

"#NotFeelingSoFabulous but a massive blessing to have you all out there sending your positive thoughts and messages," he added. "Thank you."