Did you know that some of the most iconic movie moments were improvised?

Eddie Redmayne discusses a moment during Fantastic Beasts where he had to improvise a way for his character not to be wet during the entire film.

The Super Mario Bros. Movie star Keegan-Michael Key says he improvised a song for his character, Toad.

Jeff Goldblum had a whole book of improved lines ready to go on the Jurassic World: Dominion set, and the actor has even shared an example of what he put together!

Jeff Goldblum has revealed he kept a self-penned book of Ian Malcolm lines on the set of Jurassic World Dominion... and regularly pitched them to director Colin Trevorrow.

A frequently recurring segment in C'mon C'mon was completely unscripted, so Joaquin Phoenix had to be "authentically present."

House of Gucci sees Lady Gaga taking on a new kind of role -- and apparently ad-libbing some if the film's iconic dialogue.

Free Guy director Shawn Levy explains one hilarious scene that was improvised by Ryan Reynolds after the movie had already been filmed.

David Harbour did some serious improvisation on Black Widow.

Of course the Kano actor had to get in a few lines of his own.

Vince Vaughn really ran with the whole trapped-in-a-teenage girl bit.

Directed and executive produced by Susanne Bier and created and written for television by David E. Kelley, who also serves as showrunner, the HBO limited series The Undoing follows Grace (Nicole Kidman) and Jonathan Fraser (Hugh Grant), who have a seemingly perfect life until the revelation of secrets and lies threatens to undo it all. When a violent death changes everything, Grace must figure out what that means for her family and how to pick up the pieces. During this 1-on-1 phone interview with Collider, we spoke with Bier about why she was so drawn to the script …

What are the odds of this?

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James McAvoy and Claire Foy are set to star in STX's English-language remake of the French thriller My Son, but the actors won't quite be on equal footing, as McAvoy will be in the dark, so to speak. McAvoy will play a man whose only son goes missing, so he goes to visit his ex-wife (Foy) in search of answers. To enhance the protagonist's mysterious and confusing circumstances, McAvoy will not be given a script or any dialogue, as was the case in the original 2017 French film starring Guillaume Canet. Instead, McAvoy will only …

Shannon Elizabeth improv'd in the comedy, but it wasn't for a joke.

There's three to look out for.

From writer/director Derek Cianfrance and based on the award-winning novel of the same name by Wally Lamb, the six-part HBO limited series I Know This Much Is True follows identical twin brothers Dominick and Thomas Birdsey (played in two stand-out performances by Mark Ruffalo) on their own very different life paths. It’s a family saga of sacrifice and forgiveness which begins in their present — the early 1990s — and digs into different stages in their lives as it highlights how mental illness affects everyone, including the person directly dealing with it. Rosie O’Donnell, who plays …

The truth is revealed.

The things that happen when Adam Sandler's not around.