Would you be a Harry Potter Mastermind?
Mastermind producers say they've turned down 262 applications for Harry Potter as a specialist subject as only one person can do it per series.
In 2017 that person was Madeline Grant, a website manager from London.
She managed to get 15 out of 15 - but how well would you do if you were sat in front of Mastermind host John Humphrys?