Admittedly, the Superman Returns actress had been having a rough few weeks. First came her breakup with longtime boyfriend Orlando Bloom. Then came what she thought was an attack of allergies, but "I think it turned into a little sickness," Bosworth told PEOPLE while sitting in the front row of the Sept. 14 Zac Posen show.
Still, some were concerned as the actress made the runway-show rounds and stopped in at the afterparties. "She's so small, it's frightening," says one insider who saw her at Fashion Week.
Adds another attendee and well-placed Bosworth source, "She's always been small, but now she is really, really skinny."
One possible reason: With her recent split, "she's emotionally and physically strained," says the source.
The Thinness Debate
"I think part of being an actress (is) that your body's your tool," she told Showbiz Tonight in July.
But since Bosworth hasn't filmed anything in more than a year now, some are hoping she will take a closer look at herself. "Every time I saw her," says the source, "I kept thinking, 'Please eat something.' "