Justin Bieber has given fans cause for major concern.

Late last week, the singer announced that he was postponing his tour and taking a break from his career in general -- because he's been diagnosed with something called Ramsay Hunt Syndrome.

Said Bieber in a disturving Instagram post:

"Obviously, as you can probably see from my face, I have this syndrome called Ramsay Hunt syndrome and it is from this virus that attacks the nerve in my ear and my facial nerves and has caused my face to have paralysis."

He continued at the time:

"As you can see, this eye is not blinking. I can't smile with this side of my face, this nostril will not move, so there is full paralysis in this side of my face."

The two-time Grammy winner went on to address his recently postponed concerts, saying he's "physically, obviously not capable of doing them."

He proceeded to ask fans for prayers and confirm that this condition is potentially a very big deal.

"This is pretty serious as you can see," said Bieber.

"I wish this wasn't the case but obviously, my body is telling me I got to slow down.

"I hope you guys understand.

"I'll be using this time to rest and relax and get back to 100 percent so that I can do what I was born to do."

In response, many social media users left comments of shock and support.

Others, meanwhile, were left to wonder about Ramsay Hunt Syndrome.

What, exactly, is it?

What might the future hold for Bieber?

Ramsay Hunt Syndrome is a rare neurological disorder that occurs when the varicella-zoster virus infects a nerve in the head near the inner ear.

It's often the result of one having chicken pox as a child or shingles as an adult, as the virus can lay dormant in the body for many years.

Why the virus reactivates and produces symptoms of Ramsay Hunt is not known, which makes it a challenging problem for doctors to solve.

Symptoms can include a painful rash inside the ear canal and outside the ear, at times attacking the tongue and roof of the mouth.

Due to the inner ear involvement, people with the condition can also suffer vertigo (the sensation of dizziness or things spinning around you), or tinnitus, a ringing in the ear.

Ramsay Hunt Syndrome can also cause hearing loss on the side of the face affected.

As has unfortunately been the case with Bieber, it can also cause a weakness, facial droop or paralysis on the side of the face which has been attacked by the virus.

This kind of weakness can cause difficulty with closing one eye, making facial expressions and eating, as food can fall out of the side of the weakened mouth.

The treatment?

It typically consists of steroids (such as prednisone) to reduce inflammation and pain medication.

At times, antiviral medicines that help with the herpes family, such as acyclovir or valacyclovir may be prescribed.

Justin's wife, Hailey Baldwin Bieber, experienced her own health scare in March after she was hospitalized for a stroke.

She responded on Thursday to her spouse's video by telling him "I love u baby" on her Instagram story.

Bieber, meanwhile, assured fans that he is "gonna get better" and that he was doing "facial exercises to get my face back to normal."

"It will go back to normal -- it's just time and we don't know how much time, but it's going to be ookay," he said in his video.

"Obviously my body's telling me I gotta slow down. I hope you guys understand and I'll be using this time to just rest and relax and get back to 100%."