Taking your kid to the pediatrician isn't exactly a fun day out. But families waiting to see Dr. Brenda Bass at her LA office on July 16 got a special surprise: Brad Pitt and Angelina Jolie showed up -- with their elusive 1-year-old twins, Knox and Vivienne! "I was just leaving the office as Brad and Angelina and the kids turned up," an eyewitness tells Life & Style. "Brad was wrangling the other kids, while Angie was carrying both twins. Angie told the receptionist they were there for the twins' one-year checkup."

The sighting was especially notable because the twins have been spotted out in public only one time since their birth in Nice, France, on July 12, 2008. As Life & Style has reported, the twins have both had digestive problems, and Vivienne has allergies, so Brad and Angie have kept them sheltered and indoors. On the day of the doctor's visit, "Angelina was holding the twins pretty tightly," the witness says, "but they looked like regular little babies."

For more on Brad, Angie and the kids, pick up this week's issue of Life & Style, on newsstands now!

Photo Credit: Landov