Hearthstone: Heroes of Warcraft, Blizzard's free-to-play digital card game, has topped 20 million players worldwide, according to a tweet from the game's official Twitter account.
Hearthstone hit more than 10 million players in March, following its open beta and release earlier this year. The game is available on iPad, Mac, Windows PC and Windows 8 touch devices. It's expected to launch for Android and iOS devices later this year.
At BlizzCon 2014, players competed for a $100,000 prize.
For more on Hearthstone: Heroes of Warcraft, check out our review.