So that's what your tattoo symbolizes...

Sure Matthew Lewis has had some ink on the right side of his arm for quite some time. And yes, Stranger Things became a smash hit on Netflix in just the past couple of months.

But in a hilarious new Instagram shared Sunday afternoon, the Harry Potter star revealed the true meaning behind his famous roman numerals.

"A lot of people ask what my tattoo means. Now you know," he wrote online while posing with one of the show's biggest breakout stars. "@milliebobby_brown #XI #Eleven."