Welcome to PopCrush's annual March Madness poll, where you guys get to decide which fan base in pop is the most dedicated.

It may seem cruel to pit two former best friends against each other in any competition, and maybe it is. But Demi Lovato and Selena Gomez both have fan bases whose intensity is similarly matched, so a face-off between the two only makes sense, even if it's a little painful.

Demi's Lovatics have maintained their dedication to the singer through her very public trials, including but not limited to: Her struggles with mental health, eating disorders and addiction. But part of Demi's appeal (aside from her immense talent as a vocalist) is her honesty: She's been entirely open and transparent about her personal issues and, in her quest to lessen the stigma behind mental health disorders, has helped spark a much-needed conversation about mental illness. Through all of this and beyond, Demi's Lovatics have remained loyal, unwavering in their love and support.

Selena, on the other hand, first won fans over with her Disney Channel show Wizards of Waverly Place. She continued on an upward trajectory, somehow managing to bypass the typical child star curse of growing out of your cuteness. Instead, she's accepted film roles that showcase her maturity, without alienating her devoted fan base. She's since blossomed into a bonafide pop star, too, finally discovering the type of sound that works best for her breathy vocals on her latest album Revival -- all while remaining thankful to the fans who helped her along the way.

Which fan base deserves to move on to the next round? Be sure to cast your vote in the poll below before it closes on March 9 at 11:59 PM EST.

The Evolution of Demi Lovato's Hair

Selena Gomez's Hottest Stage Looks