Had another 'who?' sighting

I just had another 'who is that?' celebrity sighting while walking to Ralphs Grocery store in Westwood. I just saw Allison Mack, the actress who plays Chloe Sullivan on Smallville (WB t.v. show about Superman/Superboy). I have to admit that I didn't even know her name until I looked it up online. But I recognized the face! She is frail-like thin in real life and walked past me quickly with a stone-cold face not making eye contact with anything. Hmmm, do papparazzi or crazy fans hound her? It sure was a lot of 'don't mess with me' attitude from such a small lady. I prefer my Dave Matthews sighting a lot better-- he smiled and gave a little head nod like a normal, friendly person.