20 Stars Who Almost Played Iconic TV Characters

From Grey's Anatomy to This Is Us, from Modern Family to The Office, a lot of our favorite TV shows would look, well, a lot different had certain casting decisions zigged rather than zagged.

Here's a look at 20 stars, including Jensen Ackles, Katherine Heigl, and Betty White, who almost played TV roles that were ultimately made famous by other actors. Sometimes the stars lost out on these choice parts; sometimes they themselves turned down the jobs.

PHOTOS: See who almost played Jack on This Is Us!

No matter how things went down, the bottom line is the same: If some nos had been yeses, the TV world we know -- and love -- wouldn't exist.

Click the arrow to see which stars almost starred in Grey's Anatomy, This Is Us, Modern Family, The Office, Friends, and more!

In the 1990s, Jensen Ackles was best known for the daytime soap Days of Our Lives, where he starred as Salem standout Eric Brady. Click ahead to see what super role Ackles almost took off with next.

In 2001, as Jensen Ackles told Smallville: The Comic, casting for Smallville's lead "came down to Tom and me." Tom, of course, is Tom Welling, who won the role of Clark Kent. In 2004, Ackles finally joined the Smallville cast as Clark's romantic rival, Jason Teague. In 2005, he was cast as one of the Winchester brothers in Supernatural -- and the rest is TV history.

A former child actor, Katherine Heigl was 20 when she debuted as Isabel Evans on the eerie WB drama Roswell. Click ahead to see which other WB series -- and role -- Heigl almost booked before boarding the extraterrestrial show.

Katherine Heigl auditioned for the Dawson's Creek pilot -- and did "great," series creator Kevin Williamson told Entertainment Weekly. "I remember we were all sort of like, 'Wow, she's good,'" he said.

But then Michelle Williams showed up, and, well, she was perfect. Williams played Creek's Jen from 1998 to 2003.

From 2018 t0 2019, Oliver Hudson starred as the divorced dad of three on ABC's Splitting Up Together. Had it not been for a fishing trip, Hudson might've been known for playing another TV father of three.

Oliver Hudson told the Ladygang podcast that he had a good audition for This Is Us. But when he was called back to read for Jack Pearson with Mandy Moore, who was in the running to play the character's wife, Hudson said he declined because he was scheduled to go fishing. Milo Ventimiglia hooked the part instead.

In 2008, Dawson's Creek vet Joshua Jackson began a five-season run as Peter Bishop on Fox's Fringe. But had it not been for a Hollywood labor war, he would've appeared in a long-running ABC hit that same year.

In late 2007, ABC announced Joshua Jackson would join the Grey's Anatomy cast as a love interest for Sandra Oh's Dr. Cristina Yang. But then, as TV Guide recounted, Hollywood writers went on strike. By the time the strike ended and business resumed, Jackson had moved on to Fringe. Kevin McKidd, meanwhile, was hired to play Yang's lover, Dr. Owen Hunt.

In 1983, Betty White hosted the NBC daytime game show Just Men! A couple of years later, she was due to play a man-hungry retiree when the show's director had second thoughts.

As The Golden Girls was coming together for NBC in 1985, Betty White was slated to play the hot-to-trot Blanche Devereaux. But because she'd played a similar character on The Mary Tyler Moore Show less than a decade prior, director Jay Sandrich suggested White instead play the innocent Rose Nyland. "And then they went out and got a real nymphomanic to play [Blanche]," White joked of Rue McClanahan at a 2006 Paley Center event.

In 2004, Rob Lowe had a decision to make: Play a doctor on a new CBS series, or play a doctor on a new ABC series. The choice he made turned out to be a great one... for another actor.

In his memoir, Love Life, Rob Lowe revealed that he was offered Grey's Anatomy "right away," but that he opted for a show called Dr. Vegas because he felt that CBS, which was the home of Dr. Vegas, had a better track record of producing drama hits than ABC, which was developing Grey's. In the end, Dr. Vegas lasted 10 episodes, while Patrick Dempsey played Dr. Derek Shepherd on Grey's for 10 years.

Following the cancellation of Friends spin-off Joey, Matt LeBlanc returned to TV in 2011 with Showtime's Episodes. But he might've made it back to the small screen sooner if he hadn't passed on the chance to play a TV dad on a new ABC comedy.

Matt LeBlanc told USA Today he was offered the role of Phil Dunphy, but that he passed on the Modern Family part because he was "not the guy for this." Indeed, he wasn't. While ABC wanted the well-known LeBlanc to play Phil, the producers' first choice was Ty Burrell. Burrell, of course, ended up with the gig. LeBlanc finally became a TV dad himself via CBS's Man with a Plan.

When Chris Pratt stopped to pose at the 2004 Teen Choice Awards, he was in the midst of his run as Bright Abbott on the WB's Everwood. While Bright was a jock, Pratt almost went on to make a name for himself as a TV nerd.

In 2006, producer Josh Schwartz hired Chris Pratt for the final season of Fox's The O.C. A year later, Schwartz was working on a new spy comedy for NBC, and Pratt was "the first guy I wanted to play" the title character. But Pratt, Schwartz said, was "destined to guard the galaxy" (after a stint on NBC's Parks and Recreation, natch). Zachary Levi ended up starring as Chuck on, well, Chuck.

Despite a wealth of movie and TV work, Craig Robinson remains best known for his first big role: as warehouse foreman Darryl Philbin on The Office. Click ahead to see which other Dunder-Mifflin character Robinson could've been known for instead.

The Office producer Greg Daniels said he mulled a "version" of The Office where Jim Halpert and Pam Beesly were an interracial couple, and Pam was played by an African-American actress. And in this iteration, Pam's boyfriend, Roy Anderson, would have been played by an African-American actor. "It would have been Craig Robinson as Roy, and Erica Vittina Phillips [Superbad] as Pam," Daniels said.

In the end, Daniels' team opted to cast Robinson as Darryl, and David Denman as Roy.

In 2012, Friday Night Lights vet Connie Britton debuted as the shimmering country star Rayna Jaymes on ABC's Nashville. But if network suits had had their way, she might have been cast that same year in another new ABC drama.

When ABC ordered the Scandal pilot, a network exec told creator Shonda Rhimes that the show's heroine -- a crack crisis-management expert -- would be a "perfect" part for Connie Britton. "I said, 'It would be, except Olivia Pope is black,'" Rhimes told The Hollywood Reporter.

Kerry Washington ended up as Scandal's star. Both Scandal and Nashville were long-running hits for ABC.

In 2004, Paul Giamatti was riding high, thanks to the Oscar-winning hit Sideways. The actor ended up on the wishlist of an NBC exec overseeing a new comedy series.

According to a New York Times story on how NBC developed The Office, the network's chief programmer wanted Paul Giamatti to play Dunder-Mifflin's dense boss, Michael Scott. But Giamatti passed -- and Steve Carell, then best known for The Daily Show, got his shot. Carell starred on The Office from 2005 to 2011.

In 2009, Ashley Judd spoke at a Washington, D.C., luncheon hosted by NARAL Pro-Choice America. If things had gone differently, she might've been speaking on the set of a CBS drama hit.

As Julianna Margulies told the The Hollywood Reporter, she was the third choice -- behind Ashley Judd and another actress -- to play The Good Wife's Alicia Florrick. Judd and the other actress (who we'll get to in a bit) both passed. Margulies won a Primetime Emmy for the role which she played from 2009 to 2016.

In 1995, Nancy McKeon, the former Facts of Life star, fronted the ensemble cast of the CBS sitcom Can't Hurry Love. One year earlier, McKeon almost won a role on another ensemble comedy series, on another network.

As recounted in the book Friends Forever: The One About the Episodes, the casting of Monica Geller came down to Nancy McKeon and Courteney Cox. NBC left the call up to Friends' creative team -- and, after a walk around the studio parking lot, the producers chose Cox. McKeon's Can't Hurry Love was canceled after one season.

In 1990, up-and-comers Craig Bierko (pictured, left) and Matthew Perry starred alongside Valerie Bertinelli in the short-lived CBS comedy series Sydney. Four years later, Bierko and Perry were both in the running for the same role on a new sitcom for NBC.

In 1994, Craig Bierko and Matthew Perry were both on the shortlist to play Chandler Bing on Friends. As the story goes, producers liked Bierko, but they really liked Perry (who'd coached Bierko for his audition). The problem was, Perry was committed to star in an ABC comedy about airport baggage handlers in the year 2194. After Bierko passed on playing Chandler, the sci-fi airport project got grounded, and Perry finally joined Friends.

Jack Lord is seen in a publicity photo from 1965 -- three years after he played a CIA agent in the James Bond film Dr. No; three years before he debuted as the original Steve McGarrett in Hawaii Five-O; and one year before he almost blasted off in what would become one of Hollywood's most iconic properties.

According to the William Shatner memoir, Star Trek Memories, Jack Lord was the first pick to play the USS Enterprise's Captain Kirk in the original Star Trek series. Lord was ruled out, however, when he asked for half-ownership of the show. When Star Trek took off on NBC in 1966, it was Shatner who was in command of the bridge.

In 1966, Martin Landau scored breakout TV fame as Rollin Hand, master of disguise, on the original Mission: Impossible. But had he wanted, Landau could've chosen an entirely different look -- and role.

As Martin Landau would tell it, he turned down the role of Star Trek's pointy-eared Spock because the highly logical Vulcan was too unemotional: "Who wants to do that?" Landau would ask.

Leonard Nimoy, as it turned out, wanted to do that. Nimoy would play Spock off and on, in TV and film, for nearly 50 years.

In 2004, Lisa Edelstein found primetime fame on Fox's House as Dr. Lisa Cuddy. House began while another iconic TV show -- that Edelstein almost landed -- was ending.

As Lisa Edelstein told Access Hollywood Live, she had a contract to play columnist-about-town Carrie Bradshaw on HBO's Sex and the City. But the deal was never inked because Sarah Jessica Parker, the producers' dream choice, said yes to the part. The jilted Edelstein never did become a Sex and the City fan: "It was too painful [to watch]," she said.

In 1983, Matthew Broderick enjoyed an early big-screen hit alongside Ally Sheedy in WarGames. Click ahead to see what hit TV show -- and character -- he might've been busy with instead.

According to Michael J. Fox, the character of Family Ties' buttoned-down Alex P. Keaton was Matthew Broderick's for the taking, but Broderick was booked. The role fell to Fox, who would star alongside Justine Bateman and the rest of his TV family from 1982 to 1989.

In 2008, Helen Hunt hit the publicity circuit to promote her film-directing debut, Then She Found Me. A year later, she waved off the chance to head up a CBS drama series.

Along with Ashley Judd, Helen Hunt was one of two actresses to pass on playing Alicia Florrick before the script for The Good Wife made its way to Julianna Margulies. Margulies told The Hollywood Reporter that her agent helped her put things in perspective: "No one will know when they watch this show that Helen Hunt was offered it before you," the rep said, per Margulies.

In 2009, Eric Stonestreet was cast as Mitchell's husband, Cam Tucker, on ABC's Modern Family. While an Emmy-winning run ensued, Stonestreet could've found comedy series fame years sooner, had a casting call gone the other way at NBC.

As Office producer Greg Daniels once told TV Guide, "Eric Stonestreet would have been Kevin if Brian Baumgartner hadn't been picked." Fortunately, things worked out for both actors -- and both shows.