Billie Eilish is among the guests on the latest episodes of the David Letterman Netflix series, My Next Guest Needs No Introduction. She shared that at age 11 she was diagnosed with the neurological disorder Tourette's syndrome. It can cause uncontrollable and unwanted vocalization. She said people sometimes misunderstand what is actually happening. She said most think she is being funny so they laugh which she finds offensive. Billie said other artists have shared with her that they also have Tourette's but she was not going to share who. She said she is happy to talk about it and she doesn't experience anything when she is on stage performing. More from buzzfeed.com.