On this photo, you have Emily Kinney and Evanna Lynch. Uncanny, isn't it? Which one was in the 'Harry Potter' series, and which one has been doing battle with zombies in 'The Walking Dead'? If you're looking for help with magic from 'Luna Lovegood', she's the one on the right. If you're looking for help fighting off the undead, go left and pair yourself up with 'Beth Greene'. We're not sure they'd be much use to you if you got them the wrong way around.
People mistake the two so often that if you enter either woman's name on Google, one of the first predicted search results suggests the other woman's name, followed by 'related'. People really have to double check all the time to work out which person's work they're watching. If you're really paying attention, Kinney has slightly darker eyes, and a more pointed chin. Chin-spotting is a useful skill when you're playing the celebrity lookalikes game!