Canadian pop singer Justin Bieber is showing early signs of making a recovery after he was diagnosed with a virus that left half of his face paralysed, according to a surgeon who specialises in face paralysis.

In a video posted on Instagram, Bieber said he had contracted Ramsay Hunt syndrome, which affected nerves in his ear and face.

He noted that his right eye was not blinking and only half his mouth could smile.

“I can’t smile on this side of my face. This nostril will not move. So there’s full paralysis on this side of my face,” he told his 240 million Instagram followers.

Bieber, 28, said he was physically unable to perform his upcoming shows but was doing facial exercises and expected to make a full recovery.

“It will go back to normal,” he said.

“It’s just time, and we don’t know how much time that’s going to be.”

Charles Nduka, a consultant plastic reconstructive surgeon in the United Kingdom and the co-founder of health charity Facial Palsy UK, said about 75 per cent of patients with the syndrome who receive early treatment, including steroids and antivirals, make a full recovery.

“I did notice in the video shared by Mr Bieber that he does appear to have some evidence of recovery, which is encouraging,” Nduka told Reuters.

Justin Bieber and wife Hailey at the Grammy Awards in April. Photo: Getty

“With facial paralysis one of the most obvious things is patients are unable to close their eye fully to blink and they are unable to smile,” Nduka added.

“Before the smile recovers, the first thing that will develop is there is increasingly symmetry in the face at rest. So, the base of the nose often elevates slightly, and the mouth becomes more even.

On the video that was shared I could see some signs that there is some early recovery.”

Nduka said he works with patients in the entertainment industry and it is important they first address any issues weakening the immune system before returning to work.

“They will be under financial pressures and all sorts of pressures to get back out there as soon as possible but doing so will only lead to longer term problems,” he said.

Bieber found fame as a 13-year-old and went on to become a global pop phenomenon with songs like Baby and Believe.

He has two Grammy wins among 22 nominations, including record and song of the year nods this year for Peaches, and album of the year for Justice which included performances from Australia’s The Kid Laroi.