When it comes to role-based switching and ditching, the talent agents in new Prime Video show Ten Percent deal with as much drama as the actors they look after. There’s Olivia Williams and Helena Bonham Carter, who discover they’ve somehow been cast in the same movie role. How will their agents sort that one out without anyone throwing their BAFTAs out of the pram?

Meanwhile Dominic West is desperate to get out of his part in an avant-garde Hamlet production when the director starts driving him crazy. And Kelly Macdonald has some tough decisions to make when she’s rejected from superhero gig Birdwoman for some less than flattering reasons (rude).

For any real-life agents out there, this casting hokey-cokey is all going to sound very familiar. Some of cinema’s most iconic movies could have looked very different if the actor who finally played the part had been the one the studio originally wanted – and the one their agents might have asked, even begged, them to take.

Take Indiana Jones. Today the character is inextricably linked with Harrison Ford, but Steven Spielberg’s original casting choice was moustachioed hunk Tom Selleck. His agents desperately tried to get him out of shooting TV show Magnum P.I so he could take the part, but failed and Selleck lost out on one of the greatest roles in pop-movie history. “It turns out I could’ve done both,” the star revealed later. “But Harrison kind of did a good job.”

It’s not the only well-known role impacted by clashing schedules. Tom Cruise was originally cast as small town dance-king Ren in 1984’s Footloose but had to ditch the role because of a clash with the filming of All The Right Moves. Rob Lowe replaced him – but managed to put his knee out onset. Finally Kevin Bacon donned his sneakers and Walkman and a movie career (and Six Degrees of Separation) was born.

Last-minute role swaps aren’t just down to date dramas and dodgy knees of course. Eric Stoltz was ‘let go’ from Back To The Future after filming had commenced as his performance was ‘too serious’ for director Robert Zemeckis. Michael J. Fox became time-travelling teen Marty McFly, and the rest is movie history.

And while we might have Al Pacino’s incredible performance as Michael Corleone in Francis Coppola’s The Godfather indelibly etched on our minds, the part was originally offered to Jack Nicholson. “Back then I believed that Indians should play Indians and Italians should play Italians,” Nicholson later explained of his decision to turn down the role.

Then there are actors who turn down roles in movies – much to their agent’s horror – which go on to be huge hits. When Batman star Michael Keaton passed on playing TV weatherman Phil Connors in Harold Ramis’ Groundhog Day, he missed out on starring in a 90s comedy classic. “I didn’t get it,” Keaton later remembered of reading the screenplay. “This guy sounds like the kind of wry, sardonic, glib young man I’ve played before. But it ended up being so great. You can’t do it better than Bill Murray did it.”

Will Smith’s instincts were similarly off when he turned down the role of Neo in The Matrix, with the role eventually going to Keanu Reeves. “I watched Keanu’s performance – and very rarely do I say this – but I would have messed it up. At that point I wasn’t smart enough as an actor to let the movie be,” Smith later generously admitted.

On a similarly blockbuster level, Gwyneth Paltrow turned down the role of Rose in James Cameron’s Titanic and Mel Gibson opted not to don a leather skirt for Ridley Scott’s Gladiator, making way for Russel Crowe’s Oscar-winning performance.

Still, the king of the missed opportunity must be John Travolta. By the early 1980s, after stratospheric hits Saturday Night Fever and Grease, Travolta’s career had drifted into the doldrums. A string of flops including Moment By Moment, Urban Cowboy and Perfect had left the superstar’s box office reputation in tatters.

Cranking the role-regret up a notch was the fact that during the same period Travolta had turned down starring parts in Splash, An Officer and a Gentleman and American Gigolo – three of the biggest hits of the era. Luckily for him, after years of stinkers, Quentin Tarantino fought for the fallen star to be cast in Pulp Fiction in YEAR and his career was reborn.

Still, while Travolta may have been having a movie ’mare, another star was making some seriously good choices. Not only did Richard Gere hoover up An Officer and a Gentleman and American Gigolo from Travolta, he also snagged the role of businessman Edward Lewis in Pretty Woman from Burt Reynolds. Establishing Gere as a go-to leading man and general swoon-some heart-throb, and making a serious cut for his agent in the process.

But after the dust has settled, and as the team at Nightingale Hart no doubt tell their talent, there’s always the next audition. And the next star turning down the role of a lifetime for them to leap on instead…

Ever wondered what it would be like to look after the rich and famous? Then check out Ten Percent, the brilliant new dramedy from Prime Video following the lives and careers of a likeable bunch of A-list agents at a fictional London firm. From the award-winning writer behind W1A and 2012, and starring Jack Davenport, Jim Broadbent, Lydia Leonard and an incredible cast of real-life stars including Helena Bonham Carter, David Oyelowo, Kelly Macdonald, Phoebe Dynevor and Dominic West, it’s your new must-binge-watch. All eight episodes of Ten Percent are on Prime Video from 28 April – for more info click here