I haven’t seen Rachel Bilson pictured with Hayden Christensen in so long, I just assumed they had fizzled out. Apparently not, Page Six says Rach was rockin’ an big diamond and telling folks on a flight to New York that she is engaged.

A Page Six spy spotted Bilson on a Virgin America flight from LA to JFK Monday night with her mom and tells us the actress is engaged to longtime beau Hayden Christensen. “A man sitting in front of her on the plane saw a ring on her finger and asked if she was married,” said our snitch, who overheard Bilson reply, “I’m not married yet, just engaged. I know I look like I’m 15, but I’m actually 27.” Her rep didn’t return calls.