It's common in casting that people who are approached for a part don't always accept it. Whether it's because of lack of interest, fiscal or scheduling reasons. Sometimes it's for the best, and other times it's for the worst. Regardless, it's intriguing to think how these characters would have turned out if they were portrayed by different thespians.
11. Leonardo DiCaprio as Leonard DiCaprio's Head on Futurama
This Academy Award nominated actor was asked by Futurama's crew to appear as himself on the show, but he declined their offer. I think they took his response well though.
10. Tom Cruise as Tom on The Simpsons
In 'Brother from the Same Planet,' Bart gets a 'bigger brother' named Tom after he lied to the Big Brothers Agency about having a destitute life and a cruel father. Tom's the personification of perfection. He's kind, erudite, a trained fighter, motorcycle enthusiast, and has a lavish lifestyle. Tom was modeled after action star Tom Cruise. The Simpsons' crew heard from series developer James L. Brooks that the actor was interested in being on the show. Yet, after they presented the role to him he didn't take it. Instead they hired Phil Hartman and he did a fantastic job.
9. Lily Tomlin as Edna Mode from The Incredibles
Comedian Lily Tomlin was contemplated for Edna Mode, but after she heard Mode's demo tape (performed by Brad Bird) she was quoted as saying, "what do you need me for? You already got it."
8. Jack Black as Gnome on The Powerpuff Girls
For the episode 'See Me, Feel Me, Gnomey,' Black was asked to play this mystical and powerful gnome, but he didn't accept the role. Jess Harnell was instead cast, but it seems that Gnome's singing voice and image was inspired by Black. Needless to say, Harnell's performance was memorizing and brilliant.
7. John Cleese as Cogsworth in Beauty in the Beast
Cleese was in mind when the writers were developing Cogsworth. However, when they approached him for the role he declined. This wouldn't be the first time he turned down a Disney role.
6. John Cleese as Zazu in The Lion King
Cleese weighed whether or not he wanted to play Zazu in The Lion King, or Jean Bob in The Swan Princess (both were released in 1994). He went with the latter as he thought Bob was a more intriguing individual.
5. Al Pacino as Two-Face on Batman: The Animated Series
At some point Scarface actor Pacino was given the role of Batman villain Two-Face, yet he turned it down for unknown reasons. Richard Moll eventually took the part.
4. Robert De Niro as Hopper in A Bug's Life
De Niro was reportedly offered to perform the voice for this miscreant, but decided to pass it up. Personally, I enjoyed Kevin Spacey's rendition of this cruel, grasshopper.
3. Billy Crystal as Buzz Lightyear in Toy Story
The Seven Sundays comedian was approached to voice the space ranger, but dismissed it . He later regretted this decision after seeing the movie, and when he was later propositioned to play Mike in Monsters, Inc. he immediately accepted.
2. Patrick Stewart as Jafar in Aladdin
Due to scheduling conflicts with Star Trek: The Next Generation, Stewart had to reluctantly pass on the part. He's named this incident as his largest contrition.
1. Angela Lansbury as Herself on Family Guy
According to the DVD commentary for 'Peterotica,' the crew tried to get legend Angela Lansbury to voice herself narrating one of Peter's erotic novels on tape. She refused due to the episode's pornographic content, and instead they featured and cast Betty White. In the end, they were pleased with White's interpretation.