Conversation so far:
how many seasons of gossip girl are there
Gossip Girl ran for six seasons
when was the first episode of gossip girl
The first episode of Gossip Girl aired on September 19, 2007
when was the last episode of gossip girl
the last episode of gossip girl aired on December 17, 2012

Question: Who plays Serena
Self-contained rewrite: Who plays Serena on gossip girl