Over the weekend, sports marketer Chris Grosse posed a question to his Twitter friends: Do you have a photo of yourself that was supposed to be a photo of someone else? Usually, when there are cameras out, you're going to smile, or pose, or otherwise prep yourself to be caught in a moment in time. But when that camera's not really pointing at you, you let your guard down -- but you get caught, anyway.
Thousand of photos flew in that answered Grosse's question in full, and it's a glorious thread to scroll through.
While most of the replies came from events like premieres, award shows and press junkets, that's kind of the fun of it. Some of these photos we've seen before, becoming historical media relics, in a way, and now the background players are making themselves known. Find the best photobombs below and vote your favorites to the top!