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When Gossip Girl premiered in 2007, it instantly became a cultural phenomenon. Viewers were captivated by the scandalous lives of Manhattan’s elite, but they were equally obsessed with the stunning cast. At the center of it all was Serena van der Woodsen, the troubled “It Girl” returning to the Upper East Side.
For years, fans have wondered about the age gap between the actors and the high school students they portrayed. One of the most common questions is: how old was Blake Lively in Gossip Girl when she stepped into Serena’s designer shoes?
In this post, we’ll break down exactly how old Blake was during filming, compare her real age to her character’s age, and explore how this role launched her into superstardom.
Blake Lively was born on August 25, 1987.

When Gossip Girl premiered on September 19, 2007, Blake Lively was 20 years old.
Filming for the pilot episode, however, began earlier in 2007. This means she was likely still 19 when she first embodied Serena van der Woodsen for the cameras. This is surprisingly close to her character’s age, especially compared to typical teen drama casting where 25-year-olds often play high school sophomores.
To truly answer how old was Blake Lively in Gossip Girl, we need to look at the timeline across all six seasons. The show ran from 2007 to 2012, covering the characters’ transition from high school to adulthood.
It is interesting to see how Blake’s age compared to her co-stars. Teen dramas are notorious for casting much older actors, but the Gossip Girl main cast was relatively young.
Seeing this data, it’s clear that casting directors did a great job keeping the ages consistent. Blake wasn’t an outlier; she was perfectly placed within her peer group.
Knowing how old was Blake Lively in Gossip Girl helps us appreciate her performance. At just 19 and 20 years old, she had to carry a massive production on her shoulders.
Before Gossip Girl, Blake had seen success with The Sisterhood of the Traveling Pants, but Serena van der Woodsen was a different beast. The character was complex—simultaneously the “It Girl” everyone envied and a lonely young woman seeking genuine connection.
Because Blake was so close in age to the character, she brought a raw, youthful energy to the role. She wasn’t an adult remembering what it was like to be young; she was living through those formative years alongside her character. This authenticity is a huge reason why Serena remains such an iconic character in television history.
By the time the show wrapped in 2012, Blake was 25 and already transitioning into a major movie star. She had filmed The Town and Green Lantern (where she met future husband Ryan Reynolds) while still working on the series.
Her time on the show covered the most critical years of young adulthood. She entered the set as a teenager and left as a Hollywood powerhouse, fashion icon, and household name.
So, the next time you are binge-watching the series and wondering how old was Blake Lively in Gossip Girl, you have your answer. She started the journey at 20 years old and ended it at 25. Her closeness in age to Serena van der Woodsen helped ground the show in reality, even amidst the wildest plot twists the Upper East Side could throw at us.
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