It's Miley Vs. Bieber -- For All Of North America -- At 2013 MTV EMA!

Miley and Justin go head-to-head to determine who will represent the continent in the Worldwide Act category. Vote now!

Miley Cyrus will take on Justin Bieber to determine just who is the Best Act in North America ... and the winner will represent the entire continent at the 2013 MTV EMA.

Yes, after Miley's Smilers carried her to the Best U.S. Act nomination — and Justin's Beliebers helped him win Best Canadian Act — the two friends (and their fanbases) will now battle it out to determine who will rep the North American region in the EMA's Worldwide Act category.

Voting is now underway to decide a winner ... with polls closing on October 31. Either Miley or Bieber will move on to face other regional nominees — from areas like Africa/India/Middle East, Japan/Korea, and Latin America, to name just a few — with 10 finalists being named on November 1.

The winner of Worldwide Act will be revealed at the 2013 MTV EMA, set to take place on Sunday, November 10, from the Ziggo Dome in Amsterdam. The show will be broadcast here in the U.S. that same day at 7 p.m. ET/PT.

Miley is also set to perform at the show, on a star-studded bill that also includes Katy Perry, Robin Thicke, Imagine Dragons, Afrojack, Snoop Dogg and the Killers.

Justin Timberlake and Macklemore & Ryan Lewis lead the field of EMA nominees with five nods each, followed Lady Gaga, Bieber, Cyrus and Thicke, with four apiece. Taylor Swift, Bruno Mars, Thirty Seconds to Mars and One Direction are also in the running for multiple awards.

Fans in the U.S. (and the rest of the world) can vote now in EMA categories like Best Song, Best Pop and Biggest Fans by visiting online, or on their mobile phones. Voting will remain open until 11:50 p.m. CET on Friday, November 8.

The 2013 MTV EMA air Sunday, November 10 at 7 p.m. ET/PT on MTV!