The last king of Greece died on Jan. 10.
The royal's TV appearance on 'The Late Show' comes the same day as his tell-all memoir's release.
The TV host is one of many famous faces reportedly forced out of Montecito, a ritzy neighborhood near Santa Barbara.
Prince Harry claims he found out his brother, Prince William, was engaged to Kate Middleton through the press in his memoir, ‘Spare.’
The Duke of Sussex's memoir is out now.
ET spoke with royal expert Katie Nicholl about the King's possible future efforts to mend fences with his son.
Tom Hanks chats with ET at the premiere of 'A Man Called Otto' in New York City.
Authorities have issued a mandatory evacuation order for Montecito, California, due to the threat of flooding in the area.
Prince Harry's mother, the late Princess Diana, has been a big topic during his press interviews for his new memoir 'Spare.'
Prince Harry's memoir, 'Spare,' will be released on Jan. 10.
Katie Nicholl, author of 'The New Royals,' tells ET that King Charles plans to invite Prince Harry to his coronation later this year.
Prince Harry reveals on '60 Minutes' that the royal family didn't invite him on their flight to see Queen Elizabeth before she died.
The Duke of Sussex opens up to Anderson Cooper in a new '60 Minutes' interview.
Prince Harry shares more details about the alleged altercation with his brother, Prince William, in a new interview with ITV.
