You've got to be living under a rock if you haven't heard Carly Rae Jepsen's smash single 'Call Me Maybe' yet. The 26-year-old Canadian songstress has been blowing up with her Justin Bieber-endorsed single, which appears on her 2012 EP 'Curiosity.'

Since 'Call Me Maybe' started taking over the airwaves, celebrities have been going lip-sync crazy to the song on viral videos. Justin Bieber, Selena Gomez and Big Time Rush member Carlos Pena teamed up to record an all-star lip-sync video to 'Call Me Maybe' along with other famous friends like Ashley Tisdale. The video finds the massive group of famous young adults acting like a bunch of giddy little kids as they mouth the lyrics to the infectious, effervescent song.

After the Biebs' viral version of 'Call Me Maybe' went viral, other famous folks started making their own videos. Katy Perry also took on the single, recording a video with a bunch of her friends while hanging out poolside. Even though there are a bunch of burly dudes singing Carly Rae's super lighthearted pop tune, the always animated 'Firework' songstress steals the show. In a somewhat surprising turn of events, Oscar-nominated '127 Hours' actor James Franco also recorded his own 'Call Me Maybe' lip-sync clip. Franco knows hardly any of the words, but that's what makes this rendition so awesome.

Check out all of the aforementioned 'Call Me Maybe' lip-sync videos and let us know which one you enjoyed the most by casting your vote below.

Watch Justin Bieber, Selena Gomez, Carlos Pena + More Lip Sync 'Call Me Maybe'

Watch Katy Perry + Friends Lip Sync 'Call Me Maybe'

Watch James Franco + His Friend Lip Sync 'Call Me Maybe'