Mischa Barton suffered heartbreak on her 21st birthday

Story: Splash News and Picture Agency

The death of her beloved pooch Bean.

Friends started worrying for the TV star when she was more then an hour-and-a-half late for her own birthday dinner in New York.

Barton's table sat at 9 p.m., but the birthday day girl - in a flowing white dress - did not show until gone 10:30pm.

But friends waiting at the Waverly Inn, a bar owned by Vanity Fair boss Graydon Carter, were not angered when they realized the heartache she had suffered over the loss of her family dog Bean.

One insider said: "Everyone was obviously really saddened for her. "She was upset by still up for celebrating, though, and ended the night with a bash at the Gramercy Park Hotel's trendy Rose Bar."