It's official: "Selfie" is the word of 2013! We're not surprised. After all, some of our favorite stars are constantly posting pics of themselves online, much to their fans' excitement.

Two celebs guilty of sharing lots of snaps are Justin Bieber and Rihanna. From goofy comments to pensive pouts, these two stars love posting their beautiful mugs on social media. Whose selfies do you like better?

Vote for Justin or Rihanna in the poll and scroll down for more pics.

Justin Bieber is all about giving back to his fans -- especially if it means posting pics of his face for them to swoon over! JB's Instagram feed is filled with shots of him smoldering into the camera (as well as thousands of comments liking it!). The 'Heartbreaker' singer also posts pics of his swag-arific life -- including a shirtless shot of him getting a massage! It pays to be a pop star!

Rihanna doesn't hold back from sharing on Instagram. Her selfies often lean toward the NSFW end of the spectrum, as she loves to flaunts some skin. However, RiRi also has a great sense of humor, which she also shows through her selfies. For instance, take this pic in which she's panicking about 'Breaking Bad.' Ah, superstars. They're just like us.