A television presenter (or television host, some become a "television personality") is a person who introduces, hosts television programs, often serving as a mediator for the program and the audience. It is common for people who garnered fame in other fields to take on this role, but some people have made their name solely within the field of presenting—such as children's television series or infomercials—to become television personalities.
Often, presenters may double for being famed in other fields, such as an actor, model, comedian, musician, doctor, etc. Others may be subject-matter experts, such as scientists or politicians, serving as presenters for a programme about their field of expertise (for instance, David Attenborough). Some are celebrities who have made their name in one area, then leverage their fame to get involved in other areas.
Examples of this latter group include British comedian Michael Palin who now presents programmes about travel (such as Around the World in 80 Days), and American actor Alan Alda, who presented Scientific American Frontiers for over a decade. Another example would be American stand-up comedian Joe Rogan, who is a commentator and post-fight interviewer in UFC. Prior to entering politics, former U.S. President Donald Trump served as a presenter for live shows such as Saturday Night Live and his own show The Apprentice, after being famed for his exuberant lifestyle and business finesse. The term is commonly used in many countries including Canada, New Zealand, The Netherlands, Liechtenstein, Barbados, Sri Lanka, India, Spain, Denmark, Greece, Australia, Egypt, Andorra, Malta, San Marino, Japan and South Korea.