Linux is pretty common in the startup world. But if your CEO is running around telling everyone what OS he uses instead of sealing deals you might want to rethink those stock options.
You probably mean the Android operating system. Every celebrity out there already uses linux on their android phones. PSA: the linux kernel is just one tiny irrelevant component of an android system. It's google's system level utilities and user applications that make android a complete operating system.
Probably not the kind of famous you're looking for, but there was this article [1] about an author who cut Amazon, Facebook, Google, Microsoft, and Apple from her life who of course would have to use Linux because no Microsoft or Apple allowed.