What on earth is Beyoncé's new 'Lemonade' project?

Less than a week after her activewear range Ivy Park hits stores worldwide, Beyoncé is back, turning the world hysterical all over again with her mysterious new project - seriously, does this woman ever sleep?
Bey dropped a 20 second teaser over her Instagram account three days ago, with a Game of Thrones backing track (?!) and no explanation except her caption '#LEMONADE 4.23 9PM ET / 6PM PT / HOB'
She's now added a full length trailer full of thunderstorms, eerie garages, explosions, whispers and more - but absolutely no explanation as to what 'Lemonade' could be.
The only lead we could find is from Beyonce's loyal fan base, The BeyHive. They tweeted back in February saying that people should get ready for a new Beyonce 'album film', even naming the film's director as Kahlil Joseph.
Is it a new album? is it a new music video? a documentary? is The BeyHive right or is Beyoncé actually on the new season of Game of Thrones?! Bey, you're killing us here!
One thing's for sure, we'll be cancelling all weekend plans to find out what the Queen has up her sleeve.