10 Funniest Improvised Lines and Moments in the Harry Potter Movies

10 Funniest Improvised Lines and Moments in the Harry Potter Movies
Image credit: Warner Bros.

The Harry Potter movies are among the biggest success stories in the movie world, bringing the magic of the movies to life.

However, some of their best moments were improvised, and the characters’ reactions are more than just acting – it’s a genuine response to an unscripted statement! There’s a surprisingly high number of these amazing moments in the Harry Potter films, and with this thought in mind, we have outlined some of the ten funniest improvised lines in the Harry Potter franchise as follows to help you discover once and for all just how talented these incredible actors are.

#10 Let Us Hope Mr. Potter is Always Around to Save the Day

During filming for the Chamber of Secrets, actor Jason Isaacs decided that his scene deserved to be a little more memorable – after all, someone as despicable as Lucius wouldn’t likely let Dumbledore have the last say, especially when his plans were foiled.

With this thought in mind, he completely improvised the line, “Let us hope Mr. Potter is always around to save the day.” It’s surprisingly chilling, but it’s also a pretty funny and apt portrayal of his character that’s hard not to smile at in future watches of the film.

#9 Don’t Worry – I Will Be

Daniel Radcliffe’s immediate and open response was even more incredible than Lucius’s improvised line: “Don’t worry – I will be.” The filmmakers were all in awe at this masterful improvised reply from an otherwise inexperienced child actor – going to show just how versatile Daniel Radcliffe was (and is) as an actor.

The instant reply from Harry that he would always be there really takes the moment by storm, and in hindsight, it’s a pretty funny (and much deserved) comeback for someone as vile as Lucius – especially considering Isaacs put poor Daniel Radcliffe on the spot.

#8 Luna’s Dancing

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During the wedding of Fleur and Bill, the books originally had Harry disguised as a Weasleys cousin to keep his identity protected – but Luna saw right through the disguise. Unfortunately, this was cut from the final film. However, Luna’s actress, Evanna Lynch, came up with a masterful alternative to this line, showing her exuberant personality instead with a wacky and out-there dance routine that really would be impossible for anyone to choreograph properly.

#7 Barty Crouch Jr’s Tongue Flick

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It might not be a line so much as a mannerism, but did you know that Barty Crouch’s iconic tongue flick wasn’t actually included in the books? This was David Tennant’s wonderful addition to the role, and the nervous habit perfectly matches Crouch Jr’s nervous and unstable nature.

#6 Holy Crickets!

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Hermione was a bit of a goody-two-shoes in the first book and film, there’s no doubt about it. However, this is perfectly represented by her statement, “Holy crickets, you’re Harry Potter!” Of course, she was always supposed to be amazed by meeting Harry for the first time, but the fact that Watson improvised this line makes it all the more impressive. And, honestly, it really did fit Hermione’s character at the time.

#5 Well Done, Draco

During the Deathly Hallows, Part II, Voldemort invites the fighters to join his Death Eaters or die after Harry is announced dead. Only Draco makes a move to join his parents, and while doing so, he passes by Voldemort. The chillingly funny aspect here, however, is that Ralph Fiennes improvised the entire hug scene – meaning that Draco’s stiffness and confusion were actually real! He had no idea what was going on, and it made this scene even better. Perhaps it’s not the time for humor, but in hindsight, it’s a pretty funny thought!

#4 Emotional Range of a Teaspoon

While Hermione’s classic statement that Ron had the emotional range of a teaspoon wasn’t an unscripted event, it’s worth noting that the actors’ response to it was completely genuine. And in fairness, we can fully understand this – how else would you say that line without breaking down in a fit of giggles?

#3 Avada-

During the Chamber of Secrets, Lucius Malfoy goes to curse Dobby, as Jason Isaacs forgot the spell he was supposed to be casting. Instead, so as not to ruin the take, he simply carried on acting, proclaiming in a strained and somewhat psychotic voice the first spell that came into his head: Avada Kedavra (the killing curse). Fortunately, with a simple click of his fingers, Dobby disarms Lucius, giving the whole scene a sort of macabre humor. Still, we’re glad Lucius ended up getting his comeuppance in the end.

#2 I Didn’t Know You Could Read

For anyone who’s read the books, Malfoy’s line during the Chamber of Secrets that he didn’t know Goyle could read – in response to Harry using Polyjuice potion, still wearing his glasses – came as a bit of a shock. However, that’s because this scene was entirely improvised. When Tom Felton couldn’t remember his line, he came up with the completely genuine line – and it was so good and fit so well that the directors chose to keep it instead.

#1 What is the Purpose of a Rubber Duck?

When it comes to Arthur Weasley, no one could have played him better than the incredible Mark Williams. However, it’s hard to believe that his iconic line from the second film during breakfast wasn’t actually written in the book itself. Arthur asks Harry, “Tell me, what exactly is the function of a rubber duck?” Of course, it’s a ludicrous statement for anyone who’s grown up with muggles, and in fairness, we don’t really know either - other than a cute accessory! Still, this unscripted line perfectly shows Arthur Weasley’s character, and we’re so glad it was added in.