What's better than a picture of one celebrity? A pic of two celebrities! Especially if one of those stars doesn't know the other is making a funny face in the background.
This, my friends, is a photobomb. And the likes of Katy Perry, Ian Somerhalder and Ellen DeGeneres have all been unsuspecting victims of the bomb at the hands of Justin Bieber, Neil Patrick Harris and Kelly Clarkson (respectively).
And that's only the tip of the photobomb iceberg. Get to clicking to check out the rest of 'em and have a good chuckle with us. They never see it coming!