The 52-year-old actor was introduced to the heir to the throne at the UK premiere of his 2004 movie "Finding Neverland", but said he could not make out what the prince was saying.
"I end up here quite a lot. I'm after the 'Sir' thing... I met Prince Charles.
"He came to the premiere of Finding Neverland, I shook his hand but I didn't understand a word he said and I don't think he understood a word I said so it wasn't very meaningful necessarily, but he seemed nice!," Depp told UK talk show host Graham Norton.