FANCY yourself as a bit of a wizard?
In celebration of the 20th anniversary of the first Harry Potter book being published, something rather magical happens when you post on Facebook about Harry Potter.
Try it out by clicking on Facebook founder Mark Zuckerberg's status here.
Or give it a go on our Facebook page.
But this hidden spell doesn't just pop up when you mention everyone's favourite thunderbolt-scarred hero, it also happens if you post or comment about any of the four houses from the books – Gryffindor, Slytherin, Ravenclaw, and Hufflepuff.
The effect works in both the desktop version of Facebook and the apps and if you missed it the first time, just click on the name for the effect to appear again.
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