Kate Middleton's Night at the Ballet

March 16, 2011— -- It was a royal date for Kate Middleton in London last night. But Prince William was not on her arm – instead the future princess hit the town with her future in-laws, Prince Charles and Camilla.

The trio attended the final performance of the Royal Ballet's "Alice's Adventures in Wonderland" at London's Royal Opera House. Although they were seated in the royal box, Kate sitting between Charles and his wife, the VIPs were able to remain unnoticed for much of the evening.

"It was only when the cast, which is vast, turned to their left to curtsy to them, that most of us realized she was there," one of the ballet's attendees told People magazine. "Kate was smiling broadly as she joined in the applause."

Kate was last seen out in public with Camilla a month ago on a lunch date at Koffman's restaurant at London's Berkeley Hotel. The two were joined by Kate's younger sister, Pippa, and Camilla's daughter, Laura Lopes.

Prince William did not join his fiance and parents at the ballet because he was flying halfway around the world. The prince is starting a five-day tour of New Zealand and Australia, visiting areas hit hard by the recent natural disasters.