Some of the most famous onscreen performances could have gone a totally different direction.
Ah-nold's iconic role was reportedly offered to Mel Gibson, who turned it down. And thankfully so, because the words "I'll be back" just wouldn't have the same effect coming from Mel.
In an interview with Sirius XM, Williams revealed he was considered for Jack Nicholson's role in the1989 Batman flick. "Supposedly at one point they offered [me] the Joker in Batman, and then it went to Jack," he said.
Nicolas Cage as 'Iron Man'
It's hard to picture the Marvel trilogy being as wildly successful without Robert Downey, Jr. starring as Tony Stark, aka "Iron Man." But this movie was a long time in the making before Rob signed on to play the comic book character.
Back in 1997, Nic Cage was one of the first actors to express interest in the part. Luckily for audiences, filming didn't actually begin until a decade later and Robert Downey, Jr was there to save the day, literally.
Check out which other stars were in the running for some of Hollywood's biggest parts.
Jennifer Lawrence may have taken home the Oscar for starring as recently widowed Tiffani Maxwell, but that role almost went to Zooey Deschanel. Producers also considered Vince Vaughn for Bradley Cooper's part.
(Reuters/The Weinstein Company)
The 2010 spy thriller, "Salt" was supposed to have a male lead portraying the title character of Edwin A. Salt and Tom Cruise was reportedly slated to play the part. But then Angelina Jolie apparently caught wind of the script and showed interest in playing the lead, and that's how Evelyn Salt came to be.
"I started, literally, on the very, very bottom," Jon Hamm says of getting the part of Don Draper on AMC's "Mad Men." "I wasn't on anybody's lists... The funny thing was, I think they went to Thomas Jane for it, and they were told that Thomas Jane does not do television."
Thomas has since clearly changed his tune, as he now stars in HBO's "Hung."
Women everywhere are quite happy with both outcomes.
The first two installation of "The Hangover" were wildly popular and a third will hit screens on May 23. All the stars in the movie became household names and revamped their careers with this laugh-out-loud comedy. But Lindsay was not one of them.
She reportedly turned down the role of Jade, the stripper, which was later given to Heather Graham. Lindsay, back in 2009, apparently felt that the script "had no potential."
Boy, was she wrong.
"The Matrix" trilogy was wildly successful with Keanu Reeves as the star, Neo. But would it have been the same if Will Smith accepted the part? Will doesn't think so.
“You know, 'The Matrix' is a difficult concept to pitch," he explains. "In the pitch, I just didn’t see it. I watched Keanu’s performance – and very rarely do I say this – but I would have messed it up."
Before Daniel Craig was dubbed the new Bond in 2006, Hugh Jackman was approached to play the MI6 agent.
"'I got a call from my agent saying, 'There is some possible interest in you for Bond, are you interested?'" Hugh Jackman recalls. "At the time I wasn't. I was about to shoot 'X-Men 2' and Wolverine had become this thing in my life and I didn't want to be doing two such iconic characters at once."
(Reuters/MGM Columbia Pictures)
The Oscar winner tried out for the role of Bella Swan in the "Twilight" series. She was likely better off spending her time working on "Hunger Games" and "Silver Linings Playbook." Leave the "Twilight" series and Razzy awards to Kristen Stewart.
Emma Stone in 'Heroes'?
The funny actress tried out for the lead in "Heroes" after starring opposite Jonah Hill in "Superbad."
"I could hear that, in the other room, a girl had just gone in and they were saying, 'You are our pick... On a scale of one to 10 you're an 11,'" Emma recalls. Hayden Panettiere was the lucky gal who got the role. "I went home and just had this meltdown," she says.
We couldn't picture her in that cheerleader uniform anyhow.
The actor was offered the role of Edward Lewis in "Pretty Woman" but ultimately declined.
He later joked with Piers Morgan in 2012 that after he saw the film and the love-making scenes with Julia Roberts, that he regretted not taking the part.
The 1988 hit wouldn't have been the same without Tom Hanks as Josh, but that role almost went to Robert De Niro. Luckily, De Niro was too expensive and the producers gave it to Tom.
(Reuters/20th Century Fox)
Susan read for the role of Rocky's love interest, Adrian (Talia Shire), but producers thought she was "too attractive" to play the part.
Quentin Tarantino recently told Vanity Fair that Daniel Day-Lewis was in the running to play Vincent Vega in "Pulp Fiction." Day-Lewis had apparently read the script and wanted in on the movie, too. But after much debate, the role eventually went to John Travolta.
The 1990 mobster flick wouldn't have been the same without Ray Liotta in the lead as Henry Hill. But if producer Irwin Winkler got his way, Tom Cruise would have starred instead.
"Tom Cruise was discussed. Marty [Scorsese, the director] wanted Ray [Liotta]," he explains. "Frankly I thought we could do a lot better."
That was until Ray won him over. "My wife [and I] were having dinner one night in a restaurant and lo and behold, Ray Liotta came over to me. He said, 'Look, I know you don't really want me for it, but...' And he sold me on the role right that evening."
Let's check out some other flicks that almost starred someone else.
(AP/Warner Home Video)
The music legend was in talks to play the dirty cop, but reportedly dropped out during contract negotiations because the handgun was too heavy. He was cautious to put added stress on his wrist, which he broke on the set of "The Manchurian Candidate."
But that wasn't the only reason he stepped away from the script. His father had also recently passed away and he wanted to spend some time doing lighter material.
Once ol' blue eyes dropped out Marlon Brando and Paul Newman were considered for the role before Clint Eastwood was ultimately cast.
(AP/Warner Home Video)
Director Cameron Crowe had originally chosen Sarah Polley to play the enigmatic Penny Lane in "Almost Famous" but changed his mind during pre-production.
“Sarah is like a Bob Dylan song, more ’60s than ’70s,” he says. “That’s why it didn’t work. Kate Hudson is Zeppelin.”
The 2000 hit ended up being Kate Hudson's breakout role.
The 2008 role that revamped Mickey Rourke's career and won him a Golden Globe, almost didn't happen. Nicolas Cage was previously in talks to star as Randy "The Ram" Robinson.
It probably all came down to the fact that nobody wants to see Nic Cage with his shirt off.
(AP/20th Century Fox)
Mark Millar, the writer and creator of the comic on which the movie was based, reportedly started the rumor that Eminem was attached to the flick. The illustrations of Wesley Gibson in his stories clearly look like the rapper.
"I'm really excited about the possibility of [Eminem] playing the lead role," Mark said at the time. "Universal have already been in talks with his people."
Apparently that wasn't actually true since Em's people came back saying it was news to them. James McAvoy ended up playing the lead.
This one is so good it seems made up, but famed footballer O.J. Simpson was considered for the part of the "Terminator" in 1984. According to one report, producers thought he was "too nice" to be taken seriously as a killer.
Turns out a jury thought that, too.
When the book series was first in negotiations to make it to the big screen, Steven Spielberg was in talks to turn it into an animated movie. He envisioned Haley Joel Osment from "The Sixth Sense" reading for Harry Potter.
Luckily for Daniel Radcliffe that plan didn't work out.
(AP/Warner Home Video)
Lots of ladies were considered for the leading role of Bridget Jones.
British actresses Kate Winslet, Helena Bonham Carter and Rachel Weisz were all in the running to play the British singleton. Ultimately Renee, a Texas native, snagged the part that would forever change her career.
Fans of "Back to the Future" almost didn't get to see Michael J. Fox in the starring role as Marty McFly.
When he was first offered the part, Michael was busy shooting "Family Ties" and had to turn down the role. So producers began filming the trilogy with Eric Stoltz.
They reportedly weren't happy with how things were going and eventually found a way to make it work with Michael J. Fox by having him film at night after "Family Ties."
Who knows if the movie would have been the cult hit it is without Michael as the star.
Molly Ringwald was a star in the '80s and reportedly the first choice to play Vivian Ward in "Pretty Woman" (1990). Some other actresses considered for the part? Meg Ryan, Kim Basinger, Sandra Bullock and Heather Locklear.
Oddly enough, Richard Gere wasn't the first choice to play Edward Lewis either. Al Pacino and Christopher Reeve were reportedly originally considered for the part.
"Nobody puts Baby in the corner" was almost uttered by tough guy Val Kilmer.
He reportedly turned down the role of Johnny in "Dirty Dancing" because he didn't want to be viewed as a heart throb.
You definitely don't have to worry about that, Val!
The lead character in "The Reader" was originally supposed to be played by Kate Winslet, but she was replaced by Nicole Kidman due to a scheduling conflict with "Revolutionary Road."
However, it seems as though Kate was meant to play the WWII vet in "The Reader" since Nicole Kidman had to bow out when she became pregnant.
Kate ultimately got the role back and it earned her an Academy Award.
(AP/The Weinstein Company)
John Travolta reportedly still regrets turning down the title role in "Forrest Gump."
But fans of the movie couldn't picture anyone other than Tom Hanks playing the slow-talking Gump.
Tom did such a good job that it snagged him his second Oscar win.
That's all I gotta say about that...
Katherine Heigl's big film debut in "Knocked Up" only happened because other leading ladies turned down the part.
"I turned down another movie because it was going to show a vagina--not mine, but somebody else's," said Anne Hathaway at the time. "And I didn't believe that it was actually necessary to the story."
The 1994 movie seemed practically made for Tim Robbins and Morgan Freeman. But if Rob Reiner was in the director's seat he would have had it differently.
He wanted Tom Cruise and Harrison Ford to star as Andy Dufresne and "Red" respectively. Luckily Frank Darabont directed the cult classic instead.
Harrison Ford may be an awesome Han Solo, but he wasn't the only one considered for the part.
Nick Nolte, Al Pacino and Christopher Walken were all considered to play the lead in "Star Wars."
(AP/20th Century Fox)
Can you picture Gwyneth Paltrow posing for her portrait in the buff, just wearing a necklace?
Neither can we.
But she was apparently considered for the lead as Rose Dewitt.
The studio also wanted director James Cameron to consider Matthew McConaughey for the part of Jack, but he wanted Leonardo DiCaprio.
Tough guy Mark Wahlberg was reportedly "creeped out" by the graphic sexual nature of "Brokeback Mountain" and turned down the part of Ennis Del Mar that was ultimately played by Heath Ledger.
Joaquin Phoenix was also considered to play Jake Gyllenhaal's character, Jack Twist.
The 1981 movie was almost made with Tom Selleck as Indiana Jones instead of Harrison Ford.
Unfortunately Tom had to turn down the role due to his recently signed contract to star as "Magnum P.I."