Justin Bieber is preparing to air his upcoming YouTube documentary, Justin Bieber: Seasons - but ahead of the premiere, Justin shocked fans by revealing that he is recovering from Lyme disease.

"While a lot of people kept saying Justin Bieber looks like sh*t, on meth etc. they failed to realize I've been recently diagnosed with Lyme disease, not only that but had a serious case of chronic mono which affected my, skin, brain function, energy, and overall health," Bieber wrote.

"These things will be explained further in a docu series I'm putting on YouTube shortly," he continued. "You can learn all that I've been battling and OVERCOMING!! It's been a rough couple years but getting the right treatment that will help treat this so far incurable disease and I will be back and better than ever."

Lyme disease, also known as Lyme borreliosis, is an infectious disease caused by the Borrelia bacterium which is spread by ticks.