LOS ANGELES        -        Canadian pop superstar Justin Bieber revealed on Wednesday that he had been battling Lyme disease and a serious case of mononucleosis but said he was overcoming his health issues.

On Instagram, Bieber noted that some people had recently criticised his appearance and suggested he was using drugs.

“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.

“It’s been a rough couple of years but getting the right treatment that will help treat this so far incurable disease,” he added. “And I will be back and better than ever.” Bieber, 25, said his health challenges were among the topics to be chronicled on an upcoming 10-episode documentary series about his life that will be released on YouTube starting on Jan. 27.