27-year-old Leighton, who married The O.C.’s Adam Brody in 2014, gave birth in August, according to US reports.
The couple began dating after they co-starred in 2011’s The Oranges, keeping their romance a secret for several months.
But after numerous red carpet appearances together, the pair confirmed they were an item, going onto have a hush-hush wedding in February 2014.
And despite never officially confirming their pregnancy news, Leighton was pictured walking around LA with her husband looking very pregnant and glowing.
Leighton’s Gossip Girl co-star Blake Lively gave birth to her first child at the end of 2014, managing to keep the news quiet until the new year.
So, at least she’s got someone to call for parenting advice eh?
Congratulations Adam and Leighton!