(NEXSTAR) — On Friday, pop star Justin Bieber announced he has Ramsay Hunt syndrome. You may be unfamiliar with the syndrome, but you likely do know of chickenpox, which is caused by the same virus.

The Mayo Clinic explains on its website that the condition, caused by a herpes virus, “occurs when a shingles outbreak affects the facial nerve near one of your ears.” The syndrome can cause not only a shingles rash but also facial paralysis and hearing loss.

Bieber, 28, said in an Instagram video on Friday that he’s currently unable to move half of his face. The singer said he’s canceling tour dates for this reason.

“It is from this virus that attacks the nerve in my ear and my facial nerves and has caused my face to have paralysis,” Bieber said. “As you can see this eye is not blinking. 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.”

The condition is somewhat similar to the better-known Bell’s palsy, though Ramsay Hunt’s effects are more severe. Bell’s is facial paralysis without a rash.

According to research published by Journal of Neurology, Neurosurgery and Psychiatry, Ramsay Hunt recovery is much harder than recovery from Bell’s palsy. Patients also may not recover completely, researchers wrote.

Other Ramsay Hunt symptoms include tinnitus, nausea, vertigo and involuntary eye movements.

“This is pretty serious, as you can see. I wish this wasn’t the case, but, obviously, my body’s telling me I’ve got to slow down,” Bieber explained Friday. “I hope you guys understand. I’ll be using this time to just rest and relax and get back to a hundred percent so that I can do what I was born to do.”

Bieber says he’s doing facial exercises and has “hope” that he’ll recover.