UPDATE: Britney Spears won this round! Vote for her in the finals by clicking here.

Welcome to March Music Madness! Here at PopCrush, we’ve selected 32 of the most iconic pop songs released from the ’80s to today (divided into brackets by decade) — and now it’s your job to vote and decide which song will be named the Greatest Pop Song of the Modern Era. May the best song win!

It's Round 4 of our Greatest Pop Song of the Modern Era tournament, and the competition is getting tight! Last round, Michael Jackson's 'Billie Jean' beat out Cyndi Lauper's 'Girls Just Want to Have Fun,' making it the fan favorite for the '80s bracket. MJ will face off against the winner of the '90s bracket, Britney Spears. In Round 3, Brit's 'Baby One More Time' barely bested the Backstreet Boys with 51% of the votes. Between Michael and Britney, who will move to the final round of voting?

Michael is undoubtedly one of pop's greatest performers. 'Billie Jean,' the second single off of 1982′s ‘Thriller,' spent seven weeks at No. 1. Even today, it's widely considered one of the best songs of the 1980s. While Michael locked down his respective decade in the Greatest Pop Song competition, can he top Britney?

Britney Spears' 'Baby One More Time' is one of her biggest smashes. In addition to topping charts worldwide, Brit's debut single was nominated for a Grammy! Although Britney has numerous albums and hit songs to her name, 'Baby' will always hold a special place in the '90s pop music canon. Is it enough to help Britney beat the King of Pop?

Who should advance to the final round on the Greatest Pop Song of the Modern Era bracket? You can vote for Michael or Britney once an hour until the polls close on April 1 at 12PM ET. We know the race is going to be tough, so vote often to help your favorite song win!

Plus: After you've voted in the Semi-Finals, check out the contest at the bottom of this page to enter to win a $100 iTunes gift card. It's a gift from PopCrush to one lucky reader for joining in on the March Music Madness fun!

Final Four