Blizzard is offering a 25 percent experience boost to anyone who plays Diablo III between May 15 and 21, to celebrate the game's first anniversary.
The buff will apply to all characters and stack on top of other bonuses, and will also award an additional 25 percent bonus to the game's Magic Find statistic. Blizzard adds that the experience bonus will stack multiplicatively, and the Magic Find bonus will stack above the game's 300 percent cap.
"Thank you for your continued support, and we wish you the best of adventures in the coming year," said Blizzard.
Last week Diablo III's in-game economy was disrupted after a bug in the 1.0.8 patch allowed exploiters to amass trillions of gold. Blizzard has said that any profits made by the now-fixed bug will be donated to charity.
Blizzard is also offering a 33 percent discount on the digital version of Diablo III when purchased through its online store.
Diablo III will also be released for PlayStation 3 and PlayStation 4 later in 2013.