Although it's the major religion of India, the Hindu celeb best-known to American audiences is Julia Roberts, who discussed her conversion in a September 2010 issue of Elle. "I've been so spoiled with my friends and family in this life. Next time I want to be just something quiet and supporting," she explained.
Other Hindu celebs: Kal Penn, M. Night Shyamalan, J.D. Salinger, Ravi Shankar