Fan voting in two Billboard Music Awards categories is now open. Right now you’re allowed to vote in the top collab and top social artist categories until Friday, May 21. Cast your vote on the Billboard website when you click here. Fans may vote on Twitter as well. To vote on Twitter for top collaboration include #BBMAsTopCollab + Collaboration Song Name in a tweet. To vote on Twitter for the top social artists include #BBMAsTopSocial + @FinalistTwitterHandle in a tweet. Check out the Billboard Music Awards on Sunday, May 23 hosted by Nick Jonas.