Making a movie can be a tiresome and draining experience. So much time, effort, and money goes into movie productions, so the last thing that the cast and crew want are bumps along the way. In addition to the pervasive fear of the movie flopping spectacularly, there are other unexpected hindrances that can take filmmakers by surprise.

Related: Adam Sandler Could've Lost His Life Had He Said Yes To This Quentin Tarantino Role

There have been multiple instances in which a movie role had to be recast in the middle of production. Such occurrences are not only irksome, but often highly expensive. The reasons for recasting roles range from members of the cast facing damning allegations, poor performances, and even the actors' deaths. Here are 10 movie roles that had to be recast mid production - and why.

10 J. Paul Getty - 'All The Money In The World'

By the spring of 2017, filming had wrapped up for Ridley Scott's All the Money in the World. The director was satisfied, the actors were satisfied, and they were ready to showcase their movie throughout the film festival circuit.

That all changed, however, when star Kevin Spacey, who played J. Paul Getty, was accused of multiple sexual assaults and gave an even more infuriating apology. Subsequently, Scott made the decision to reshoot the movie with Christopher Plummer in the role instead. The recasting paid off, as Plummer was widely acclaimed for his performance and received an Oscar nomination.

9 Dumbledore - 'Harry Potter And The Prisoner Of Azkaban'

Beloved wizard Dumbledore was played by Richard Harris in the first two instalments of the Harry Potter franchise. But during the filming of Harry Potter and the Prisoner of Azkaban, the actor became gravely ill with lymphoma. Bravely, Harris nonetheless went to work and filmed some of his scenes.

But tragically, he succumbed to the cancer and director Alfonso Cuarón had to make the heart-breaking decision to recast the role with Michael Gambon.

8 Marty McFly - 'Back To The Future'

While the role of Jennifer had to be recast for the second movie, the first Back to the Future picture had actually been filmed with another lead actor entirely. Though the role remains Michael J. Fox's most iconic, he wasn't the original Marty McFly.

The movie was filmed with Eric Stoltz as Marty, but director Robert Zemeckis wasn't happy with his performance. The director found him to be too intense for the role and cast Fox instead.

7 Max - 'The Secret Life Of Pets 2'

In the first The Secret Life of Pets movie, lovable Jack Russell dog was voiced by Louis C.K. Well, it turned out that the man behind the character was not so loveable in real life.

During the filming of the sequel, Max had to be recast with Patton Oswalt following sexual misconduct allegations against C.K., all of which the comedian admitted were true.

6 Brian O'Conner - 'Furious 7'

The late Paul Walker was a staple of the Fast and Furious franchise. But when he unexpectedly died in a car crash in 2013, producers were left wondering how to complete Furious 7.

Related: This Is The True Origin Of 'Fast And The Furious'

Walker had already filmed many of his scenes, so his brothers, Caleb and Cody, were cast in a bittersweet attempt to complete the movie, which ultimately ended up serving as a eulogy for the deceased star.

5 Paddington - 'Paddington'

Although we associate the mellifluous voice of Paddington Bear with the charming Ben Whishaw, he was originally played by a decidedly different actor: Colin Firth. The English gent was involved in the movie's production, but the filmmakers had to make the difficult decision to recast the voice of the titular bear, as things simply weren't working out with Firth.

As director Paul King explained, "We love the voice and we love the bear, but as our young bear came into being, we agreed that the two didn't seem to fit." Subsequently, Ben Whishaw was cast instead, which proved to be a wise choice.

4 Shrek - 'Shrek'

It's difficult to imagine the green ogre Shrek voiced by anyone other than Mike Myers. But he wasn't the first choice. In fact, SNL star Chris Farley had recorded almost all his lines for the iconic role, but tragically died during production.

Related: What Mike Myers Really Thought About Playing Shrek

Mike Myers was then brought on to voice Shrek, but he ordered that his lines be changed completely as an act of respect towards the departed comic.

3 Zee - 'The Matrix Reloaded'

Almost 20 years after her untimely death, Aaliyah remains an immensely popular singer among fans. But she was also a talented actress, having starred in Romeo Must Die. Accordingly, the Wachowskis decided to cast her as Zee.

Tragically, Aaliyah died in a plane crash during production. The filmmakers then had to make the unenviable decision to recast the character, with Nona Gaye filling in for the late star.

2 Meg Altman - 'Panic Room'

Nicole Kidman was initially cast as protective mother Meg Altman in David Fincher's 2002 thriller Panic Room. But the Australian actress suffered a knee injury during filming, forcing her to pull out of the movie.

Jodie Foster was brought onto the project instead, but after her now legendary role in The Undoing, we can't help but wonder how the movie would have turned out with Kidman in the leading role.

1 Gellert Grindelwald - 'Fantastic Beasts 3'

Fans eagerly await the release of the third Fantastic Beasts movie, but many are upset that Johnny Depp will not be reprising his role as Gellert Grindelwald. Although he was initially cast in the third instalment of the franchise, Warner Brothers requested that he step down from the role.

This was due to the British courts ruling that claims that Depp is a "wife beater" are "substantially true". Subsequently, Danish actor Mads Mikkelsen was cast as Gellert.

Next: Hollywood Wanted Leonardo DiCaprio To Change His Name To This