Justin Timberlake fans are feeling downright disappointed in a star they feel they've come to know over his many years in the spotlight.

If untreated, Lyme disease can lead to a cascade of complications, including fatigue, severe headaches and neck stiffness, arthritis, rashes and heart palpitations. Patients can also experience dizzy spells, shortness of breath and nerve pain. In rare cases, Lyme can lead to meningitis.

The pop singer said he decided to share his diagnosis “to shed some light on what I’ve been up against behind the scenes.”