US TV
The actor's contract is not being picked up, but the door will apparently be left open for him to appear at a later date to wrap up Ethan's story.
Executive producer Rebecca Rand Kirshner Sinclair said of season two: "If Gossip Girl is about youth in New York, I want to [make 90210] about youth in L.A. and Beverly Hills."
She added: "The show tried to be a lot of things to a lot of people in its first season. I think the centre lies with the generation of kids that are in high school now. I'm not interested in casting people for stunt value."
Milligan's co-star Matt Lanter, who plays bad boy Liam, has recently been promoted to a series regular.
Tube Talk
'Freaks and Geeks': Tube Talk GoldTube Talk Gold heads back to the '80s and remembers Freaks and Geeks.
2012-13 Season
John Stamos to star in 'Little Brother'The former Full House actor will star in the comedy pilot Little Brother.
US TV Interviews
'Celebrity Apprentice' Debbie Gibson Q&ADebbie Gibson opens up about her Celebrity Apprentice experience.
US TV Ratings
'Vampire Diaries' soars to 3m for The CWThe Vampire Diaries and The Secret Circle perform well for The CW.
