"Improviso" isn't a Harry Potter spell, but it sure sounds like one, and the term is appropriate for the film versions of J.K. Rowling's stories about the boy wizard. With an impressive cast of British actors, both kids and adults, the series' eight films were bound to contain some unscripted Harry Potter moments. Over the years, interviews with various cast members and crew have revealed some of the unscripted lines and moments in Harry Potter.
The improvisers include Daniel Radcliffe, Ralph Fiennes, Jason Isaacs, and even Emma Watson, despite playing perhaps the franchise's least spontaneous character, Hermione Granger. Holy cricket!
When Draco Tells Goyle (Harry) He Didn’t Know He Could Read - ‘Chamber of Secrets’
In Harry Potter and the Chamber of Secrets, Draco (Tom Felton) asks Goyle (actually Harry, who has taken Polyjuice Potion) why he is wearing glasses (Harry forgot to take his off), and Goyle/Harry says he wears them for reading.
Draco's response - "I didn't know you could read" - was a Felton ad-lib.Great acting moment?
When Voldemort Torments Everyone At The End - ‘Deathly Hallows: Part 2’
In Harry Potter and the Deathly Hallows: Part 2, during the unsettling moments after Voldemort (Ralph Fiennes) announces that Harry is dead, he taunts those in the crowd surrounding him. According to Lucius Malfoy actor Jason Isaacs, Fiennes randomly picked different people to torment during each take:
In this giant confrontation, Ralph was let loose, and he was utterly terrifying. We shot it for weeks, and you never quite knew who he was going to turn on, what he was saying... It kept an entire courtyard full of extras and actors on their toes...Great acting moment?
When Arthur Weasley Asks Harry About The Purpose Of A Rubber Duck - ‘Chamber of Secrets’Video: ?YouTube
After Harry arrives at the Weasley home in Harry Potter and the Chamber of Secrets via Arthur Weasley's enchanted Flying Ford Anglia, the Muggle-obsessed Mr. Weasley (Mark Williams) asks Harry: "What exactly is the function of a rubber duck?"
According to actor Chris Rankin, who played Percy Weasley, the line was improvised.Great acting moment?
When Crabbe Starts To Stand Up To Cheer For Hagrid - ‘Chamber of Secrets’
During the final Great Hall scene in Harry Potter and the Chamber of Secrets, the students and faculty all give Hagrid a standing ovation when Dumbledore praises him - well, everyone except students at the Slytherin table. Vincent Crabbe (Jamie Waylett) does start to rise, but Draco drags him back down.
Waylett made the unscripted choice to attempt to stand up.Great acting moment?