Each week, Mashable picks a popular song, finds 10 covers of it and asks you to vote for your favorite.
Well, now his biggest hit since then, "Not Over You," is facing the similar fate of becoming a sing-along classic.
With dozens upon dozens of covers of the song on YouTube, we decided to round up 10 awesome ones for you. Listen to them and then vote for your favorite in our poll.
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To listen to more covers used in past YouTube Cover Song Face-Offs, click here.
Which "Not Over You" Cover Is Your Favorite?**The winner of this poll will be selected Dec. 23 at 9 a.m. ET.
Dec. 4 Face-Off Winner: Christina Grimmie
YouTube star Christina Grimmie won Mashable's most recent face-off with her cover of "It Will Rain" by Bruno Mars. Grimmie's YouTube videos have been viewed more than 237 million times. She is finding success offline, too. Most recently, Grimmie snagged the American Music Awards trophy for Female New Media, which honors the woman who is most effectively using digital and social media to propel their careers and connect with fans. She also performed with Taio Cruz after winning an online competition to share the stage with him.
Here's a collection of covers and an original song (video seven) from Grimmie.