The host of a talk show may already be a celebrity, or may become one as their show becomes popular. Some are professionals or experts in a field of knowledge, such as psychology or business. Others are well-known performers who can converse well with others. Guests on a talk show may also be experts in a field of knowledge or work, longtime professionals, or new and familiar celebrities, performers or athletes. Sometimes guests are members of the public who do something that interests others, such as inventors and authors, or someone who comes to public attention through a disaster or mishap. 