Gossip Girl star Leighton Meester is to announce her engagement to boyfriend Sebastian Stan, according to U.S. reports.

The pair met on the set of the hit show last year after Stan played a recurring role alongside Meester's character Blair Waldorf.

And the actress is allegedly eager to keep the happy news under wraps - she has only announced the engagement secretly on social networking site Facebook, according to New York gossip column PageSix.

A representative for Meester has refused to comment.

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(This news article provided by World Entertainment News Network)