Fan Army Face-Off: Rihanna's Navy Battles 5 Seconds of Summer's #5SOSFAM

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Rihanna performs during her "Anti World Tour" at Barclays Center on March 27, 2016 in New York City.

In this week’s showdown for Billboard's Fan Army Face-Off, Rihanna’s Navy takes on 5 Seconds of Summer’s #5SOSFAM. Boy bands are known to have the craziest fandoms, but with a nearly 20,000-vote lead, the Navy might be too strong for the Australian group’s mega-following.

With only five years under their belt, pop/rock band 5 Seconds of Summer first started rallying fans on YouTube. The boy band gained more traction with their Billboard 200 No. 2 EP She Looks So Perfect and their self-titled debut album 5 Seconds of Summer. The boys received the support of One Direction, joining their Take Me Home Tour in 2013 and Where We Are Tour in 2014. Since, the #5SOSFAM has brought the Australian heartthrobs worldwide stardom.

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Rihanna’s Navy, on the other hand, is more than a decade in the making. Rihanna was first recognized as a top-selling dance-pop artist with her hit “Pon de Replay” in 2005 from her debut studio album Music of the Sun. The pop star’s third studio album Good Girl Gone Bad (2007) was RiRi's start as a charts regular. It was Rihanna’s 2012 appearance in the film Battleship that coined the fan army’s name The Navy. Within the last year, Rihanna released Anti (which peaked at No. 1) and started the Anti World Tour.

Rihanna Fan on Being Part of the RihannaNavy: 'She Knows That She's Not a Role Model'

While the Navy sees their commander as the “Only Girl (In the World)," the #5SOSFAM “Don’t Stop” when it comes to supporting their favorite mates.

There are three days left for the current round of Billboard’s Fan Army Face-Off -- vote for your fave now!