Movie roles often become synonymous with the actors who play them. The more iconic the film and/or the role, the stronger this impression becomes. It seems impossible that any actor besides Marlon Brando could have played Don Vito Corleone in The Godfather, or that anyone except Michael J. Fox could have brought Marty McFly to life in the Back to the Future franchise. But what currently seems obvious and indelible was not always so, and often the parts that now seem most perfectly cast almost went to other people. Even so, when the role is especially famous, it's jarring to see what might have been.

A different interpretation of a critical role might have affected the tone of the film as a whole and resulted in a completely different movie. Forrest Gump starring John Travolta would not have been the same movie as Forrest Gump starring Tom Hanks. Most of the following films' casting ended up being perfect despite the fact that the actors may not have been the first choice to play that particular role. Nevertheless, it's fun to speculate about what might have been had the casting process gone differently. Here are 15 times different actors almost starred in your favorite movies.

RELATED: From 'Uncut Gems' to 'Spencer': 7 Actors Who Gave Great Performances While Cast Against Type

Emily Blunt - Black Widow, Iron Man 2 (2010)

Emily Blunt's character Emily in 'The Devil Wears Prada' is the anti-heroine audiences love to hate
Image via 20th Century Fox

It’s difficult to imagine anyone other than Scarlett Johansson as Black Widow in the Marvel Cinematic Universe. However, when Natasha Romanoff was set to make her debut appearance in Iron Man 2, it was Emily Blunt who was initially offered the role. In an interview with Howard Stern, she revealed that a contractual obligation to act in the film Gulliver’s Travels forced her to turn down the part, and referred to this turn of events as “a bit of a heartbreaker” for her.

Christina Applegate - Elle Woods, Legally Blonde (2001)

christina-applegate-anchorman
Image Via DreamWorks

The script for Legally Blonde came to Christina Applegate right after she had finished the tv sitcom, Married With Children, in which she played ditzy blonde daughter Kelly Bundy. Applegate told Entertainment Tonight that she wasn’t interested in playing Elle Woods because she felt that Woods had too many similarities to Kelly Bundy, a role she wanted to branch out from. “I got scared of kind of repeating myself," she said. "What a stupid move that was, right?”

Jack Nicholson - Micheal Corleone, The Godfather (1972)

Jack Nicholson resting his hand on his car in Chinatown
Image via Paramount Pictures

Nobody other than Francis Ford Coppola wanted Al Pacino to play Micheal Corleone in The Godfather. Paramount was set on a star like Robert Redford, Dustin Hoffman, or Jack Nicholson, with Nicholson even getting an offer for the part. However, Nicholson turned down the role. He had, at the same time, received offers for The Last Detail and Chinatown, which he thought were more interesting projects. He also thought that Michael should be played by an Italian, and was unhappy with the idea of being on the same set as Marlon Brando and not sharing any scenes with him (something that the version of the script he read convinced him would be the case).

Orson Welles - Don Vito Corleone, The Godfather (1972)

Orson Welles as Charles Foster Kane in Citizen Kane
Image via RKO Radio Pictures

Marlon Brando was always Francis Ford Coppola’s first choice for the role of Don Vito Corleone. However, Paramount objected to the choice, and in an interview with the New Yorker’s Micheal Sragow, Coppola recalls that one executive told him “Francis, Marlon Brando will never appear in this picture, and I instruct you never to bring him up again.” In his book Leave The Gun, Take the Cannoli: The Epic Story of the Making of the Godfather, journalist Mark Seal reveals that screen legend Orson Welles wanted the role so much that he directly lobbied Mario Puzo, the author of the novel on which the movie is based. Welles was also the preferred choice of Paramount studios. Luckily, they eventually caved to Coppola’s insistence that no one but Brando could do justice to the role.

Winona Ryder - Mary Corleone, The Godfather Part III (1990)

Winona Ryder as Joyce in Stranger Things
Image via Netflix

Sofia Coppola’s casting as Mary Corleone in The Godfather Part III by her father, the film's director, has always been rife with controversy, with her performance being almost universally panned from the moment of the film’s release. The part was originally supposed to go to rising star Winona Ryder. Andy Garcia, who played Vincent Corleone, told Insider that within only a few days of Ryder's arrival on set she suffered a nervous collapse and ended up having to depart from the project because of her health. While in most instances on this list, the actor who ended up with the role in question turned out to be a perfect fit, Sophia Coppola is a notable exception -- though Garcia believes her performance was "unjustly judged."

Emilia Clarke - Anastasia Steele, 50 Shades of Grey (2015)

Emilia Clarke as Daenerys Targaryen in Game of Thrones
Image via HBO

Emilia Clarke was initially approached for the role of Anastasia Steele (Dakota Johnson) in 50 Shades of Grey but turned it down because of the required nudity. She told The Hollywood Reporter that she had been disappointed in the treatment she received after her nude scenes in Game of Thrones, and didn’t want to repeat the experience. In her words “the last time I was naked on camera on [Game of Thrones] was a long time ago, and yet it is the only question that I ever get asked because I am a woman...I'm pigeonholed for life."

John Travolta - Forrest, Forrest Gump (1994)

John Travolta as Vincent Vega in Pulp Fiction

Tom Hanks won an Oscar for his portrayal of Forrest Gump, and the role remains one of his most memorable to this day. However, John Travolta was actually the studio's first choice for the part. He turned it down in favor of playing Vincent Vega in Quentin Tarantino’s Pulp Fiction. The role revitalized Travolta’s career, and Travolta even competed against Hanks that year for the Academy Award for Best Actor. Hanks took home the Oscar that night; nevertheless, with Pulp Fiction enjoying the iconic status that it does in part due to Travolta’s performance, it seems the actor made the right choice.

Toshiro Mifune - Obi-Wan Kenobi, Star Wars: A New Hope (1977)

close-up of Toshiro Mifune staring in The Hidden Fortress
Image via Toho

In writing Star Wars: A New Hope, filmmaker George Lucas took heavy inspiration from the films of Japanese director Akira Kurosawa – in particular, his 1958 samurai adventure film The Hidden Fortress. The character of Obi-Wan Kenobi (Alec Guinness) in particular is based on The Hidden Fortress character Makabe Rokurōta, played by legendary Japanese actor Toshiro Mifune. Lucas consequently wanted Mifune to portray Obi-Wan Kenobi in A New Hope. At a 2015 event announcing Tokyo's first comic con, Mifune's daughter revealed that her father turned the offer down because he was concerned that a potentially low-budget sci-fi film would cheapen the image of samurai.

Al Pacino - Han Solo, Star Wars: A New Hope (1977)

Vincent Hanna holding a gun and looking intently off camera in Heat
Image via 20th Century Studios

The role of Han Solo feels practically synonymous with Harrison Ford’s portrayal of the iconic character. Even so, it was Al Pacino who was initially offered the role. The Godfather actor told MTV that he turned it down because he found the script too confusing. He added, “I was in The Godfather. They didn’t care if I was right or wrong for the role, if I could act or not act.” In the end, this self-awareness allowed for one of the most memorable performances in the Star Wars franchise.

Hugh Jackman - James Bond, Casino Royale (2006)

Wolverine-Hugh Jackman-X-Men

Hugh Jackman told Variety in 2017 that he received the offer to star as James Bond in Casino Royale right before filming for X-Men 2 started. Jackman felt that the James Bond scripts had become too ridiculous and that he wanted them to “become grittier and real.” He ultimately turned down the role, saying “I was also worried that between Bond and X-Men, I’d never have time to do different things.”

Will Smith - Neo, The Matrix (1999)

will-smith-pursuit-of-happiness
Image via Colombia Pictures

Keanu Reeves only became Neo in The Matrix after Will Smith had already turned down the life-changing role. In a video on his YouTube Channel, Smith recalls that the reason said no to the movie was because of the confusing way the Wachowskis pitched it to him. Finding the pitch vague and nonsensical, he turned down the part and went on to star in critical and commercial failure Wild, Wild West instead. Though in retrospect it seems he made the wrong choice, Smith admits that Keanu Reeves was the best choice for the role.

Chris Farley - Shrek, Shrek (2001)

chris-farley-black-sheep
Image Via Paramount Pictures

SNL alum Chris Farley was originally supposed to portray Shrek in the Dreamworks animated fantasy of the same name. Unfortunately, the comedian died of a drug overdose in 1997, after recording 85% of his character’s dialogue. The role ultimately went to his SNL costar Mike Myers, who gave the character his distinct Scottish brogue. He also changed the character’s personality somewhat - according to Farley's brother, Kevin Farley, Farley’s take on Shrek was apparently more innocent and vulnerable, and more subdued, than Myers’ version is.

Natalie Portman – Juliet, Romeo + Juliet (1996)

Natalie-Portman-as-Jane-Foster-staring-in-Love-and-Thunder
Image via Marvel

Leonardo DiCaprio’s and Claire Danes' chemistry is off the charts in Baz Luhrmann’s sun-soaked adaptation of William Shakespeare’s Romeo and Juliet. But the role of Juliet almost went to a different rising star – Natalie Portman, who at 13 years old had already demonstrated her ability to take on mature roles with films such as The Professional and Heat. In an interview with Vpro Cinema, Luhrmann looks back on the film and remembers that he and the studio worried that the age gap between her and 21-year-old DiCaprio was inappropriate. They fired Portman and hired 17-year-old Claire Danes instead.

Eric Stoltz – Marty McFly, Back to the Future (1985)

Eric-Stoltz-back-to-the-future
Image Via Universal Pictures

Though Michael J. Fox made Marty McFly famous, he wasn’t the first person cast in the role. That dubious honor goes to Eric Stoltz, who even completed his footage as Marty before being fired. Filmmakers decided he wasn’t the right fit for the role -- according to Christopher Lloyd they wanted someone with more "comedic flair." As for whether we’ll see an Eric Stoltz cut of the movie any time soon, Back to the Future co-creator Robert Gale revealed to Den of Geek that the answer is almost definitely no – out of respect for Stoltz if anything else. "Seeing the Eric Stoltz footage, it's not very good," Gale explains. “When someday you see that, you’ll say, ‘Oh, okay. I understand why they recast him.'”

Tom Selleck – Indiana Jones, Indiana Jones and the Raiders of the Lost Ark (1981)

magnum pi tom selleck image
Image via CBS

Indiana Jones could have had a mustache. The role was originally offered to Tom Selleck, who completed a successful screen test opposite Sean Young as Marion Ravenwood (Karen Allen). Unfortunately for Selleck, CBS forced him to turn the job down, since they had him under contract for Magnum P.I. As is so often the case, it all turned out for the best, since Harrison Ford is a cultural icon as the famous archeologist and adventurer. However, watching the screen test provides an interesting glimpse of what might have been...and unlike the parallel universe in which John Travolta plays Forrest Gump, it's not a reality I'd mind living in.