Watch: Blake Lively Shares Never-Before-Seen 'Gossip Girl' Photos for Show's 18th AnniversarySpotted: Blake Lively feeling nostalgic. In honor of the 18th anniversary since Gossip Girl's premiere, Serena van der Woodsen herself celebrated the show by posting a carousel of behind-the-scenes snapshots taken throughout its six-season run. "This show was my college. It was my education, my social life, my hardwork, my late nights and early mornings, my teacher," the 37-year-old captioned the never-before-seen pictures she posted on Instagram.