Will Smith turned down the role of Neo in "The Matrix," paving the way for Keanu Reeves to become the iconic hero of the sci-fi trilogy.
Jim Carrey said no to Willy Wonka in "Charlie and the Chocolate Factory," allowing Johnny Depp to bring his eccentric charm to the whimsical character.
Hugh Jackman almost missed out on Wolverine. Dougray Scott was initially cast but had to step down due to scheduling conflicts, leading Jackman to become the iconic mutant.
Emily Blunt had to decline the role of Black Widow in the MCU due to scheduling conflicts, opening the door for Scarlett Johansson to become the formidable spy.
Tom Selleck was the first choice for Indiana Jones, but commitments to "Magnum, P.I." led to Harrison Ford taking on the adventurous archaeologist.
Sean Connery turned down Gandalf in "The Lord of the Rings," allowing Sir Ian McKellen to bring his magical touch to the wise wizard.
Matthew McConaughey passed on Jack Dawson in "Titanic," ultimately letting Leonardo DiCaprio and Kate Winslet create the timeless love story we know today.