The danger of appearing on a chat show is you never know what their researchers are going to dig up on you.
This famous actress appeared on Jimmy Kimmel where the talk show host revealed "literally the most embarrassing photo of my whole life", featuring her in her peak Harry Potter fan stage.
That actress is Legend of Tarzan's Margot Robbie.
She said the picture was taken on her 13th birthday, which she celebrated by sitting in bed with a cup of tea and "clearly really enjoying myself" reading JK Rowling's fifth Harry Potter book.
She pointed out the glasses she was wearing which "I didn't actually need" - the actress has 20/20 vision but lied to get glasses so she could look like Harry Potter.
It all came about with regards to David Yates, who directed Robbie's latest film Tarzan, as well as several of the Harry Potter films - "which is highly exciting for a massive Harry Potter nerd".
You can watch the full interview here: