On Thursday, the singer shared a lengthy message via Instagram about his Lyme disease diagnosis, which he called "relentlessly debilitating."

Chris Kirkpatrick is in awe that his former ‘NSync bandmate Justin Timberlake performed a full tour amid a battle with Lyme disease. "I've always known my little bro was tough - but this tour showed me a whole new level of strength,

Chris Kirkpatrick took to Instagram to shower praise on Timberlake, who revealed Thursday that he was diagnosed with the debilitating disease.