Following Justin Timberlake's completion of his recent tour, the star revealed on Instagram that he had been battling Lyme disease.

However, the Cry Me A River performer isn't the sole celebrity to have fought the condition. Kelly Osbourne has previously been candid about her struggle and revealed in her 2017 autobiography that she was bitten by a tick in 2004.

Lyme disease can prove challenging to diagnose accurately as many of its symptoms mirror other conditions, leaving sufferers with exhaustion, joint aches, and even cognitive impairment.

Lyme disease is transmitted to humans via tick bites - yet Kelly remained unaware for years that she was afflicted, reports The Mirror US. 

Kelly revealed in her memoir, There Is No F---ing Secret: Letters From a Bada-- Bitch, that she experienced "traveling pain" which ranged from stomach aches to throat soreness.

In 2013, she suffered a seizure and received an epilepsy diagnosis.

She detailed how medics couldn't discover an effective treatment, explaining, "My prescriptions kept piling up. I couldn't sleep, so they gave me Ambien. When Ambien made me nauseated, they switched me to Trazodone, but that gave me acid reflux, so then I had to take an antacid every day. I took cranberry extract and antibiotics because one medication made me prone to getting urinary tract infections."

The agony became so severe that she told her family, "I can't live like this anymore. I'm a vegetable.

"What annoys me is that this is a real, real disease. It almost killed me. And it's incredible, and you know this better than anyone, how someone can take one sentence and make it seem so negative," Kelly wrote.

"Nothing about it is negative, because I will do anything to raise awareness for it because I almost died from it," she added. "It is a debilitating disease that most of the time goes misdiagnosed."

She eventually consulted an alternative health practitioner, Philip Battiade, who ordered tests and diagnosed Kelly with stage III neurological Lyme disease in 2014, 10 years after she was first bitten by a tick.

According to the Mayo Clinic, stage III's most common condition in the United States is arthritis in the joints, mostly the knees.

It also creates swelling, stiffness, and pain.

Stage III symptoms can begin between two to 12 months after a tick bite.

Lyme disease is treated with antibiotics - sometimes intravenous antibiotics if the Lyme disease is advanced.

It's unclear what stage of Lyme disease Justin Timberlake has, but the star has been open about how it affected him, calling it "relentlessly debilitating."

He wrote in his Instagram post, "If you've experienced this disease or know someone who has - then you're aware: living with this can be relentlessly debilitating, both mentally and physically."