It happens pretty often. Actors meet while working together on a show, and the next thing you know, they hit it off.
These 15 couples dated while working on their shows, sometimes playing a couple on the show while also dating in real life. Or, in some cases, they played siblings.
Either way, those relationships (and the subsequent break-ups) definitely had an affect on their shows.
Here are 15 couples whose real-life romances ruined their shows.
Nina Dobrev and Ian Somerhalder
While their characters dated on The Vampire Diaries, Nina Dobrev and Ian Somerhalder dated in real life. Their relationship eventually ended, which was apparently one of the reasons Nina Dobrev decided to leave the show.
Michael C. Hall and Jennifer Carpenter
They played siblings (okay, not traditional ones) on Dexter, but Michael C. Hall and Jennifer Carpenter began dating shortly after they met, and then running off to elope. They stayed together for a while, but Michael C. Hall reportedly had multiple affairs, and the couple split. Still, they had to keep playing siblings after they were divorced. Awkward!
Kaley Cuoco and Johnny Galecki
While their characters were in and on-again, off-again relationship on The Big Bang Theory, Kaley Cuoco and Johnny Galecki were dating in secret. Their relationship lasted about two years.
Rachel Bilson and Adam Brody
The O.C.'s Rachel Bilson and Adam Brody dated while they worked on the show, but their relationship didn't exactly work out. Later, Bilson stated that the relationship caused stress on set.
Kat Dennings and Nick Zano
Kat Dennings and Nick Zano dated in real life while filming 2 Broke Girls. It didn't last, though, and Dennings is now dating Josh Groban.
Joshua Jackson and Katie Holmes
Joshua Jackson and Katie Holmes started dating when they met on the set of Dawsons Creek, but actually split up before their characters got together. That really had to be weird for them.
Naya Rivera and Mark Salling
Glee stars Naya Rivera and Mark Salling starting dating before their characters got together, but their break-up wasn't amicable in the slightest.
Milo Ventimiglia and Alexis Bledel
Gilmore Girls stars Milo Ventimiglia and Alexis Bledel dated for about three years while filming Gilmore Girls. It didn't work out in real like for for their characters, but a lot of funs are still rooting for Team Jess when the revival series lands at Netflix.
Leighton Meester and Sebastian Stan
Was everyone of Gossip Girl hooking up, or what? Leighton Meester and Sebastian Stan dated in real life and on screen, and their characters broke up right about the time they did.
Penn Badgley and Blake Lively
Gossip Girl stars Penn Badgley and Blake Lively dated for three years during the show's run, ending their relationship two years before the show itself ended. Their characters, on the other hand, ended up getting married.
Chad Michael Murray and Sophia Bush
One Tree Hill Stars Chad Michael Murray ad Sophia Bush got married soon after meeting on the show, the marriage didn't last. Their divorce contributed to Chad Michael Murray leaving the show.
Keri Russell and Scott Speedman
Keri Russell and Scott Speedman dated in real life during the later seasons of Felicity, but that relationship didn't work out either.
Emily VanCamp and Dave Annable
Emily VanCamp and Dave Annable played siblings on Brothers and Sisters while dating in real life. Their on-screen relationship then changed drastically when they found out they actually weren't related, and then fell in love with one another. Their real life relationship contributed to that story.
Jennifer Garner and Michael Vartan
Here's another couple who got together both on-screen and off. Alias stars Jennifer Garner and Michael Vartan broke up before the show ended, and Garner went on to marry Ben Affleck. Garner and Vartan reportedly got back together for a short while after Garner and Affleck divorced.
Jennifer Morrison and Jesse Spencer
House stars Jennifer Morrison and Jesse Spencer also dated both on-screen and off. But their real-life split was apparently a reason why Morrison ended up leaving the show.