Worst acting ever?
Jennifer Aniston in a St. Jude's commercial. It's just bad. She just seems really uncomfortable with the kid on camera. I'm sure part of this is that the Us Weekly reader in me sees Jennifer Aniston in a charitable commercial and thinks "I'm sure everyone thinks she is doing this because of Brad and Angelina." But even with an uncynical eye, the acting is really wooden. (The kid, a St. Jude's patient, is really adorable.)
Here's the link.