Cecily von ziegesar interviewing

“I’m pretty sure the first interview I ever did for Gossip Girl — I think it was 2002 — was with Avenue,” Cecily von Ziegesar says one recent afternoon, speaking over the phone.

It’s no surprise Avenue goes so far back with the best-selling novelist, whose series about a Manhattan private school clique was adapted into an era-defining television series in 2007.

Von Ziegesar attended the Nightingale-Bamford School, and is descended from German aristocracy — her very name evokes a turreted ancestral schloss, nestled in the misty Bavarian Alps.

Nonetheless, she insists she was only ever an observer of the privileged set.

“I never felt like I fit in with the Upper East Side Manhattan situation. So, I was always writing those books as an outsider, looking in,” she says.

Recently 50, with a son entering tenth grade and a daughter on the way to college, she has now written a book that reflects her current stage of