Bill Hader and Anna Kendrick played siblings (also Santa’s children) in the Christmas movie Noelle and have been “‘quietly’ dating for over a year.”
2.
Georgia Moffett played David Tennant’s daughter on Doctor Who. They were rumored to have started dating around 2008 then got married in 2012, and have been together ever since.
3.
Susan Dey and David Cassidy played siblings on The Partridge Family, and while Susan had a huge crush on David, he didn’t initially feel the same. David shared that he finally gave in but “couldn’t think of her as anything but [his] sister.”
4.
Maureen McCormick and Barry Williams played siblings Marcia and Greg Brady on The Brady Bunch and dated for a bit in real life — Barry was actually Maureen’s first kiss!
5.
John Travolta played Diana Hyland’s son in TheBoy in the Plastic Bubble and then began dating in 1976 until Diana’s death in 1977.
6.
Matthew Broderick and Jennifer Grey played siblings Ferris and Jeannie Bueller in Ferris Bueller’s Day Off and started secretly dating while they made the film.
7.
Eleanor Tomlinson and Harry Richardson played sister in brother in Poldark and then dated for about a year until their breakup in 2011.
8.
Emily VanCamp and Chris Pratt played brother and sister duo Bright and Emily Abbott on Everwood, then dated for three years.
9.
Ian Somerhalder and Maggie Grace played step-siblings Boone Carlyle and Maggie Rutherford on Lost, then began dating after their characters were killed off the show.
10.
David and Tamela Mann have been married since 1988 but starred as father and daughter in the movie and TV versions of Meet the Browns and have reprised their role in several Tyler Perry Cinamatic Universe projects.
11.
Michael C. Hall and Jennifer Carpenter played brother and sister on Dexter, eloped in 2008, got divorced in 2010, and then continued to play the roles until the end of the series in 2013 and returned for the 2021 revival.
12.
Shannen Doherty and Jason Priestley played brother and sister on Beverly Hills, 90210, and years after the series ended, Jason admitted to briefly dating Shannen along with some of his other co-stars.
13.
Katherine Heigl and Jason Behr played brother and sister on Roswell and got together shortly after meeting on set.
14.
Michael Emerson and Carrie Preston have been married since 1998 and Carrie ended up getting to play Michael’s mother on Lost all because of a joke.
15.
Lauren Graham and Peter Krause played siblings Sarah and Adam Braverman on Parenthood, and after years of trying to keep Peter in the friend zone, Lauren finally started dating quietly dating him during the run of their show.
16.
Tom Hanks and Rita Wilson played siblings in Sleepless in Seattle just five years after getting married in 1988.
17.
Evan Rachel Wood and Shane West played siblings on Once and Again when Rachel was 12 and Shane was 21, nine years later, they reunited and started dating.
18.
Kirstie Alley and Parker Stevenson married in 1983 and then went on to play siblings on the miniseries North and South: Book II.
19.
Amy Poehler and Will Arnett were actually married in 2003, before they went on to play the sibling-skating-duo Stranz and Fairchild Van Waldenberg in Blades of Glory.
20.
Milo Ventimiglia starred as Hayden Panettiere’s uncle on Heroes, they began dating during the show’s run in 2007 and stayed together for about two years.
21.
Drew Barrymore and David Arquette played siblings in Never Been Kissed and years later David confirmed that the two had dated years before (even though Drew denied it).
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