Shingles is linked to the chickenpox virus that many people can get when they’re children.
According to the charity Facial Palsy UK, if the immune system becomes depressed and is less able to fight off infection, the body can become vulnerable to a reactivation of the chickenpox virus.
It says stress is often a trigger as it can weaken the immune system, and people who are stressed are more likely to suffer from infections.
Justin had earlier told fans he had been doing facial exercises to regain movement, but that it would still take time to recover.”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 said in the three-minute video.
He also smiled and blinked, showing his followers how the right side of his face did not move.