It’s begun. All fans have the opportunity to sign up to all BlizzCon contests to participate onstage on August 21.  If you have been eagerly awaiting this, go subscribe asap while it lasts.

Blizzard Quote:
You can now sign up for our on-site BlizzCon contests by visiting the BlizzCon Contest page. The Dance, Soundalike, and Costume contests will be taking place live on-stage August 21 at BlizzCon. If you wish to take part in these contests it’s important you sign up now, before the event. We’ll be emailing registered participants before the event with more information on what to do once they reach the convention center. Visit the BlizzCon Contest page to read the rules and sign up now!

https://eu.blizzard.com/blizzcon/contests/