Morena Baccarin & Ben McKenzie
We couldn't help but race to the red phone and launch the Batman signal when the Gotham co-stars confirmed in September 2015 that they were expecting a baby together.
Camille De Pazzis & Scott Speedman
The Last Resort costars shared a smooch in Hawaii just weeks after Speedman reportedly split from girlfriend Teresa Palmer.
Emily VanCamp & Josh Bowman
The Revenge costars started dating for real in 2011 and got married in December 2018 in the Bahamas.
Nina Dobrev & Ian Somerhalder
Though they kept it quiet for a year, these stars of The Vampire Diaries are still going strong.
Sophia Bush & Austin Nichols
The One Tree Hill costars have been dating off and on since, well, her marriage ended to her other OTH costar, Chad Michael Murray.
Jared Padalecki & Genevieve Cortese
Wicked chemistry! No wonder Sam and Ruby's Supernatural sex scenes were so convincing: The real-life lovers swapped blood vows in late February.
Leighton Meester & Sebastian Stan, Gossip Girl
Watch out, Chuck Bass—the attraction between Queen B and Carter Baizen is for reals: the actress-singer and the showbiz stud had a real-life romance—until she called it quits.
Evangeline Lilly & Dominic Monaghan
With just as many twists and turns as the six seasons of Lost, this romance went everywhere but the sideways universe, until they finally called it quits in 2009.
Ed Westwick & Jessica Szohr, Gossip Girl
Spotted! Upper East Sider Chuck Bass and Brooklyn babe Vanessa Abrams settle their differences before some other opponents (and Cheech!) at a Knicks-Lakers game.
Blake Lively & Penn Badgley, Gossip Girl
Their star-crossed relationship is endlessly frustrating to fans of D and S, and offscreen, Blake and Penn kissed each other goodbye after three years together.
Anna Paquin & Stephen Moyer, True Blood
Was it love at first bite when these two role-played their romance between a Southern gentleman vampire and telepathic human waitress? The stars kept their relationship secret during the show's first season but tied the knot in 2010.
Dying for more Bill & Sookie? Check out our True Blood pics!
Jennifer Love Hewitt & Jamie Kennedy, Ghost Whisperer
Melinda Gordon's supernatural colleague told Ryan Seacrest the dating actors "have an intense connection." Unfortunately, it wasn't stronger than the one J.Love shared with former costar and ex-fiancé Ross McCall: She and Kennedy called it quits after a year.
Anna Torv & Mark Valley, Fringe
John Scott and Olivia Dunham's clandestine tryst in the pilot—and their romance's sudden end (death and betrayal) and rekindling (mind-sharing hallucinations)—embodies everything covert and weird about this show. The actors stuck to script by wedding in secret in late 2008, but the now former costars parted ways this spring.
Jessica Stroup & Dustin Milligan, 90210
These two hotties date other people on the show and weren't shy about PDA, but called it quits after two years together.
Jamie-Lynn Sigler & Jerry Ferrara, Entourage
Turtle came out of his shell for a mafioso's daughter, but his Soprano love song didn't stop after the credits rolled. The two actors, both native New Yorkers, started dating after her cameo (playing herself) on his hit series—but the relationship ended two years later.
Michael C. Hall & Jennifer Carpenter, Dexter
These on-screen siblings married in 2008, separated in 2010, and were officially divorced in late 2011—just as Carpenter's character on Dexter started thinking she was in love with her older brother. Now that's an... interesting family dynamic.
Karina Smirnoff and Maksim Chmerkovskiy, DWTS
Mario Lopez's former on- and off-screen partner danced her way into another castmate's heart and became engaged instead to her fellow Ukrainian costar. The couple called it quits nine months later, but apparently with no hard feelings.
Alyson Hannigan & Alexis Denisof, Buffy and Angel
As part of the Scooby Gang, Willow and Wesley fought vampires and other big bads, but something else will now be keeping the married former costars awake at night: their second child! The couple's first child, daughter Satyana, was born March 24, 2009.
Milo Ventimiglia & Hayden Panettiere, Heroes
We always felt a little squeamish about these Heroic half-siblings hooking up, so if the cheerleader has tossed her pom-poms to someone her own age, we say yay!
John Slattery & Talia Balsam, Mad Men
Roger Sterling unceremoniously divorced his wife, Mona, for a younger woman, but we can report that the real-life acting couple have been happily wed for more than 10 years. This is Talia's second marriage—her first husband was...wait for it...George Clooney. (Yes, that George Clooney.)