In the NBC program Heroes, I worked as a college professor on Orientation, Episode 1, Season 4. We filmed it on the campus of the University of California, Los Angeles.
Our chief handler was a tall, Rastafarian-haired guy named Moose.
When we first hit the set, Moose, and several PA's placed 250 background actors. A guy playing guitar. Two students throwing a Frisbee. A couple of girls handing out flyers.
For my first scene, I walked down the stairs near the UCLA's Powell Library, glanced at the clipboard I was carrying, and walked toward Royce Hall, passing star Hayden Panettiere on the sidewalk.
We did that scene about ten times.
The second scene was more complicated. Starting at the top of a long outdoor hallway in front of Royce Hall, I walked the entire length of the hall, passing students and other teachers along the way. I ended up walking past Hayden Panettiere who is talking to another woman right in front of the camera.
After five takes, Moose asked me to stop halfway down the hall, speak to two students, and then continue.
This sequence put me within twelve inches of Hayden Panettiere a half-dozen times.