2.Dianna Agron wascasttheday before the pilot forGleebegan shooting.

Series creatorRyan Murphysaid Agron “ruined the part” for him because she “humanized” Quinn.

“She can cry at the drop of a hat.

Kurt Russell in costume as R.J. MacReady from the film "The Thing," wearing a brown leather jacket with fur collar

So now her character has a conscience, a soul, and great vulnerability.”

3.Viggo Mortensenwas castafterproduction began forLord of the Rings.

He replaced Stuart Townsend, who was deemed too young for the role andfired the day beforefilming began.

Quinn Fabray, character from Glee, standing in a hallway wearing a cheerleading outfit and holding a gym bag

“I felt unprepared,” Mortensenrevealed.

I also felt awkward because I’d never been in a position of replacing another actor."

5.Stanley Tucci similarly replaced another actor days before production began.

Viggo Mortensen in "The Lord of the Rings"

When Gosling showed up on set to film, Jacksonfiredhim.

Tucci was cast in the role instead.

6.Speaking of Tucci, heacceptedhis role inThe Devil Wears Pradaonly 72 hours before the start of shooting.

Screenshot from "Thor"

“I was cast at the 11th hour,” TuccitoldEntertainment Weekly.

It touched you emotionally.

It’s the perfect Hollywood movie."

Screenshot from "The Lovely Bones"

“It’s a miracle I survived the first day.

I was so scared.

It was only later that I realized that everybody was scared,” she said.

Stanley Tucci in a pinstripe suit, patterned tie, and glasses as his movie character

Fletcherearnedan Oscar for her portrayal.

“It was a last-minute audition, and I got it.

It was crazy, a whirlwind of emotions,” Garza revealed.

Screenshot from "One Flew Over the Cuckoo's Nest"

9.A week beforePrison Breakbegan shooting, it didn’t have either of its leads.

Wentworth Millerwas castonly a week before shooting.

10.And Dominic Purcellwasn’t officially castuntil three days prior to filming.

Screenshot from "Scary Stories to Tell in the Dark"

He onlyhadfour days to prepare for the role.

A few days later, Sheffield was heading to Louisiana, too, to shoot.

15.David Hayman was cast days beforeBullstarted shooting because the original actor had dropped out.

Screenshot from "Prison Break"

“I had no time to think about it,” Haymanrevealed.

“I love Paul Andrew Williams’s work.

His movies and work are challenging.

Screenshot from "Prison Break"

I love the cast.

So it was a no-brainer for me to do it.”

Director David Mickey Evans called meeting Renna a “godsend” as he was perfect for the role.

Marty McFly from Back to the Future stands confused in front of a "Welcome to Hill Valley" sign, wearing a denim jacket

By Monday, he was on set.

He replaced Dennis Hopper, who left the cast due to “creative differences.”

He wasnominatedfor an Oscar for his work on the film.

Screenshot from "Godless"

21.Ben Whishawwas castas the voice of the titular teddy bear inPaddingtonafter the film was shot.

“That was a bit scary because it was late in the process.

We’d shot the film, but it was the right call,” recalled producer David Heyman.

Screenshot from "The Maze Runner"

Firth’s exit was in June, and the film was set to come out in November.

22.Thesame happenedwith Scarlett Johansson inHer.Samantha Morton had originally been cast and worked on set throughout filming.

They recast Johansson in the role in the 11th hour, re-recording the character’s dialogue.

Screenshot from "Bull"

Screenshot from "The Sandlot"

Character Corporal Hicks in military gear from the movie "Aliens."

Screenshot from "The Truman Show"

Screenshot from "All the Money in the World"

Closeup of Rafe Spall

Ben Whishaw next to a giant Paddington bear

Closeup of Scarlett Johansson

Hugh Jackman as Wolverine, wearing a leather costume with three metal claws protruding from each hand