Okay, music fans! PopCrush's 2015 March Madness bracket is here, and this year's competition is going to be a tough one! We're pairing up fanbases -- yep, that's you guys -- against each other to determine which artist truly has the best fans.

Let's break it down. There will be four rounds of voting. Each one will have two fanbases going head-to-head. We'll be updating the brackets each round so you can keep track of who is facing off against who. As the voting gets more intense, so will the choices! Voting in Round 3 began on March 24 and already the competition is fierce.

The last round of voting will begin on March 31 and the Best Fanbase winner will be announced on April 6. Sound good? Click the button below to start voting!