WATCH: Professor Snape saying "Harry Potter" on helium!

Alan Rickman appeared on 'The Tonight Show Starring Jimmy Fallon' and decided to take some helium balloons with him to settle a score.

Rickman jokingly confronted the show's host about the 'RIckman-off' he had with Benedict Cumberatch a couple of years ago and presented the balloons as 'truth telling machines'. The guest and host then took in the helium with some hilarious results.

First Fallon decided to get Rickman to say his Harry Potter character's name asking, ‘Can I ask you a question? You did eight movies with a character, what was the name of that character again, that you did in all the movies based on the books?’ As the audience giggled Rickman drew in a deep breath and answered 'Professor Snape.' He was then asked the name of ‘the boy with the scar’ and said: 'This is very difficult but it’s Harry Potter.’

Rickman discussed some of the pranks from the Harry Potter set including the tiem he and Michael Gambon, who played Dumbledore, put a fart machine in Daniel Radcliffe’s sleeping bag while working on the Prisoner Of Azkaban movie.

Watch the Rickman video above and see the 'Rickman-off' below:

• Alan Rickman
• Harry Potter
• Hellium
• The Buzz
• The Tonight Show Starring Jimmy Fallon