TV shows become iconic for many reasons, the storylines, the characters and often the actors who play them.
Over the decades, whether it's dramas, comedies or period pieces, big shows have left their mark on viewers.
But would that have still been the case if different actors had taken on important roles within those shows?
It turns out, some of TV's biggest shows - and biggest characters - almost had different actors involved.
And even though those actors are household names, it's hard to imagine them as the TV characters we came to know and love played by someone else.
Here's just some of the A-list stars who turned down roles in major TV shows.
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Kristin Davis - Monica Geller in Friends
Monica Geller was famously played by Courteney Cox in smash hit sitcom, Friends from 1994 to 2004.
But during the audition process, another brunette beauty almost landed the part, Sex and the City star Kristin.
Kristin, 59, previously revealed during an appearance on The Late Late Show with James Corden: "I think I was one of, like, 8,000 young ladies who read for Monica and Courteney Cox got her.
"Courteney and I were in the same yoga class at the time and we used to hang out. The rest of us were, like, unemployed actor waitresses types and we would hang out after class."
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She continued: "One day, Courteney was like, 'Hey, guys. Do you want to come car shopping with me? We were like, 'Wow, car shopping!' [Courteney] said, 'I did this pilot, I'm feeling really good about it. I think I'm going to buy a Porsche.'
"We were like, 'Wow, is she for real?' It was Friends, and it did go very well."
Thankfully Kristin also got her big moment - and no doubt big money too - when she landed the role of Charlotte in Sex and the City in 1998.
Matthew Broderick - Walter White in Breaking Bad
Breaking Bad was a huge hit when it aired from 2008 to 2013, but Bryan Cranston wasn't the first choice for lead character Walter White.
Producers admitted in a chat with that: “We all still had the image of Bryan shaving his body in Malcolm in the Middle.
"We were like, ‘Really? Isn’t there anybody else?"
They tried Matthew Broderick and John Cusack but both actors turned it down.
It turns out Bryan, 68, was able to play a darker role after all, and his turn as Walter won him a slew of awards including four Emmy Awards for Outstanding Lead Actor.
Brian Cox - Robert Baratheon in Game of Thrones
Brian, 78, is an acclaimed actor with many impressive roles under his belt, none more so than Logan Roy in Succession.
However, he almost had a role in another huge show, Game of Thrones.
Brian previously revealed: "I'm often asked if I was offered a role in Game of Thrones — reason being that every other b****r was — and the answer is, yes.
"I was supposed to be a king called Robert Baratheon, who apparently died when he was gored by a boar in the first season.
"I know very little about Game of Thrones, so I can't tell you whether or not he was an important character, and I'm not going to Google it just in case he was, because I turned it down."
The role went to British actor Mark Addy instead.
Pedro Pascal - Marcel in The Vampire Diaries
The Vampire Diaries was a must-watch for many teens during its run from 2009 to 2017.
But when it comes to the role of Marcel, Charles Michael Davis had some stiff competition.
Show creator Julie Plec told Entertainment Weekly: "One of the other people who read opposite Charles for that part was Pedro Pascal, who I loved.
"I was obsessed with him, but he was just on the older side."
Rob Lowe - Dr. Derek Shepherd in Grey's Anatomy
McDreamy won the hearts of millions of women - and no doubt many men - when Patrick Dempsey portrayed the dishy doctor in Grey's Anatomy.
But we're sure Rob Lowe would have made just as many viewers hot under the collar if he had accepted the role of Derek Shepherd in the hit medical drama.
However, Rob, 60, he opted to star in another medical drama instead, Dr. Vegas.
Unfortunately for Rob, that series didn't last very long, but he doesn't regret it, saying: "Had I done Grey's, I wouldn’t have been in Parks and Recreation. That alone for me is enough."
Katie Holmes - Piper in Orange is the New Black
Orange is the New Black was a game-changing show and a huge hit for Netflix during its run from 2013 to 2019.
Taylor Schilling landed the lead role of Piper, but former Dawson's Creek star Katie also showed interest in the sometimes racy role.
Creator Jenji Kohan told E! News: "I met with her, she had other things to do.
"And also, in the beginning, no one knew what this was."
Maya Rudolph - Eve in Killing Eve
Maya Rudolph, 52, has had a stellar career thanks to being a cast member of Saturday Night Live and appearing in hit films including Bridesmaids.
However, she had the chance to try a different sort of role as Eve Polastri in hit series Killing Eve.
Despite being a huge fan of Fleabag and wanting to work with Phoebe Waller-Bridge who wrote and produced the series, Maya turned the role down.
She explained that the show would have required her to relocate to Europe for several months, as it filmed in cities across the continent, and that wasn't feasible at the time due to being a mother-of-four.
Eve was played by Sandra Oh, who won a Best Actress award at the Golden Globes in 2019 for the role.
Matt LeBlanc - Phil Dunphy in Modern Family
Having already won a legion of fans for playing Joey Tribbiani in Friends - a role that Vince Vaughn was turned for - Matt LeBlanc could have picked up even more if he had accepted the role of Phil Dunphy in Modern Family.
But having starred in one of the biggest sitcoms of all time, maybe it's no surprise Matt didn't want to take on another.
Matt, 57, said: "I remember reading it thinking, this is a really good script, [but] I’m not the guy for this.
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"I'd be doing the project an injustice to take this. I know what I can do, I know what I can’t do."
The role of Phil went to Ty Burrell and he won two Emmy's for Outstanding Supporting Actor.
Friends facts and figures
Dig into the facts behind the iconic 90s sitcom starring Jennifer Aniston, Courteney Cox, Lisa Kudrow, Matt LeBlanc, David Schwimmer and the late Matthew Perry.
- Friends debuted on September 22, 1994. It ran for a decade, airing ten seasons and a whopping 236 episodes.
- The emotional finale, which aired on May 26, 2004, was watched live by 52.5 million viewers in America, making it one of the most-watched TV finales of all time.
- Friends also won a ton of awards over the years including a BAFTA, a Golden Globe, 6 Primetime Emmys, 2 SAG Awards, and 12 People’s Choice Awards.
- It was set in New York but filmed at Warner Bros. Studios in L.A.
- Friends almost had a number of different titles - sitcom creators David Crane and Marta Kauffman considered monikers like Friends Like Us, Insomnia Café, and Six of One before finally settling on Friends.
- The show’s iconic theme song was also meant to be different - Friends’ original theme song was Shiny Happy People by R.E.M. which was used for the unaired pilot episode, Friends Like Us. It was eventually changed to I’ll Be There For You by The Rembrandts.
- David and Marta originally planned for the show’s main couple to be Monica and Joey, but they weren’t romantically compatible unlike Monica and Chandler who had natural chemistry.
- The cast of Friends made a pact not to date or hook up - there really was no Ross and Rachel off-screen. “We didn’t want to jeopardise any of the great relationships and friendships we had established. It was kind of an unspoken rule," David revealed.
- The cast always stuck together though, even negotiating their salaries increases as a group. When they started out their each earned $22,500 per episode but that steadily increased to $1,000,000 per episode by the finale season.