Here are some of the most well-known hosts:
* United States: The current host is Jimmy Kimmel, taking over from Terry Crews who replaced Chris Harrison. Before that, the iconic host was Regis Philbin.
* United Kingdom: The current host is Jeremy Clarkson, replacing Chris Tarrant who hosted the show for its initial run.
* India: The current host is Amitabh Bachchan.
* Australia: The current host is Eddie McGuire.
There are many other international versions of "Who Wants to Be a Millionaire" with their own hosts. If you tell me which version you are interested in, I can give you a more specific answer.