Watch: Selena Gomez Feels "Freedom" After Sharing Her Mental Health StrugglesRobbie Williams is facing a new health challenge. The "Angels" singer shared that he was diagnosed with Tourette syndrome, a neurodevelopmental disorder characterized by rapid, repetitive and involuntary muscle movements or sounds called "tics." For Robbie, however, those involuntary tics aren't external but internal. "I've just realized that I have Tourette's, but they don't come out," the 51-year-old explained during the Oct. 2 episode of the I'm ADHD! No You're Not podcast. "They are intrusive thoughts that happen.