1. Tim Roth - Severus Snape, Harry Potter and the Sorcerer's Stone
Can you imagine if our beloved Professor Snape was played by someone other than Alan Rickman? Turns out Roth decided to pursue his role as General Thade in Planet of the Apes. Win-win!
2. Carey Mulligan - Lisbeth Salander, The Girl with the Dragon Tattoo
Carey auditioned for Lisbeth three times, but failed to land the lead. However, she went on to star in Drive with Ryan Gosling, so all is well in the world.
3. Nicolas Cage - John Bender, The Breakfast Club
Cage was reportedly considered for the role, but they couldn't afford his salary requirements. John Cusack was then cast for Bender, but John Hughes ultimately pinned Judd Nelson for the character.
4. Britney Spears - Allie Calhoun, The Notebook
Ms. Spears, along with Jessica Biel and Reese Witherspoon, was rumored to be considered for the role of Allie, but Rachel McAdams stole the show.
5. Jennifer Lawrence - Bella Swan, Twilight
JLaw auditioned for the part of Bella, but lost out to Kristen Stewart. Luckily for us, Jennifer is now the lead in The Hunger Games trilogy.
6. Will Smith - Django, Django Unchained
Quentin Tarantino said he wrote the screenplay with Will in mind, but the actor reportedly turned down the role because he wanted the lead, which he assumed was the part played by Christoph Waltz.
7. Tom Cruise - Tony Stark, Iron Man
Cruise was rumored to be the star and producer of Iron Man in the late '90s/early '00s, but supposedly didn't think the script was strong enough. Thankfully, Robert Downey Jr. was the perfect casting choice.
8. Ashton Kutcher - Patrick Verona, 10 Things I Hate About You
Ashton Kutcher was beat out by Heath Ledger and failed to secure the part. Probably because the casting director couldn't ignore Ledger's good looks and sexy accent.
9. Gwyneth Paltrow - Rose DeWitt Bukater, Titanic
Gwyneth was up for the role, but lost to the lovely Kate Winslet. If Kate hadn't been cast as Rose, she and Leo wouldn't be BFFs and that would be a damn shame.
10. Leonardo DiCaprio - Max Dennison, Hocus Pocus
It would've been great if Leo played Max in this movie, but he turned down the role to star in What's Eating Gilbert Grape. That's a good excuse.
11. Jessica Lange - Elise Elliot, First Wives Club
Jessica was originally considered for the role of Elise (as based on the book), but the producers wanted the comedic element and rewrote the character to be more glitzy. The part was then offered to Goldie Hawn.
12. Thomas Jane - Don Draper, Mad Men
Thomas Jane was reportedly selected to play Don Draper, but apparently turned it down because he doesn't "do television." Ironically, he went on to act in HBO's Hung. Jon Hamm is incredibly handsome and he does society a service by invading TV on Sunday nights.
13. Julia Roberts - Leigh Anne Touhy, The Blind Side
Julia turned down the role of Leigh Anne, and Sandra Bullock accepted the part. Even though Bullock's standard rate was $10 million and the movie only had a $35 million budget, she agreed to take a pay cut to play Mrs. Touhy.
14. Matt Damon - Jake Sully, Avatar
Both Matt Damon and Jake Gyllenhaal were considered for the part of Jake Sully, but James Cameron decided to go with the Aussie, Sam Worthington.
15. Emily Blunt - Natasha Romanoff, Iron Man 2
Blunt was SO close to playing the Black Widow, but had to pull out due to scheduling conflicts.
16. Freddie Prinze Jr. - Peter Parker, Spider-Man
We could have seen Freddie's face on the big screen, but he lost out to Tobey Maguire.
17. Lindsay Lohan - Regina George, Mean Girls
Lindsay was originally cast as Regina, but reportedly turned down the part because she didn't want people to base her personality off the character.
18. Jim Carey - Jack Sparrow, Pirates of the Caribbean
Jim Carey was considered for the role of Jack Sparrow, but didn't get the part. He can bring the laughs (most of the time), but Depp manages to make a dirty, drunk pirate look sexy.
19. Christina Aguilera - Alison Scott, Knocked Up
Apparently Anne Hathaway originally had the role but left due to creative differences. Then Christina was reportedly offered the part, but she decided to focus on her music career instead.
20. Al Pacino - Han Solo, Star Wars
The role of Han Solo was offered to Pacino, who said he turned it down because he "didn't understand the script."