In all the spoilers we've heard about the season premiere, there was never any official word on what really happened to Chuck after the season 3 finale. Well we've finally got some spoilers that'll hopefully clear that right up!
It seems like Chuck has amnesia in the promos for the Gossip Girl episodes in Paris. Please tell me that isn't true. — Jill
MICKEY: It's more accurate to say that Chuck wants to forget certain things. Mostly though, Gossip Girl's petit voyage is inspired by the immortal Spin Doctors, in that there are two princes, both of whom are royally screwed when it comes to their feelings about Blair.
Source: TV Guide