A family source tells PEOPLE that the Grammy winner's diagnosis has "brought clarity to a series of unexplained issues" as Biel has been "incredibly supportive"

Pop singer Justin Timberlake announced that he has been struggling with Lyme disease, bringing attention to a growing public health threat. Timberlake, 44, said in an Instagram post Thursday that he was “shocked for sure” by his diagnosis after he had been “battling some health issues” and feeling unwell during his Forget Tomorrow World Tour.

Many celebrities, including Justin Timberlake, allegedly contracted Lyme disease; here's the symptoms and best ways to treat it.