UPDATE: Namco Bandai has provided further info and a European release date:
"Crown of the Sunken King, the first chapter in this DLC trilogy, will be available in Europe and Australasia on July, 22, 2014 for PC and Xbox/July 23 for PlayStation 3, followed with the DLC launches of Crown of the Old Iron King on August 26, 2014 for PC and Xbox/ August 27 for PlayStation 3 and Crown of the Ivory Kingon September 23, 2014 for PC and Xbox/ September 24 for PlayStation 3. A Season Pass program is also available for the entire The Lost Crowns trilogy via Steam for PC and PlayStation Network from today."
It's set in a different, sunken world within Dark Souls 2's Drangleic.
ORIGINAL STORY: Just published on developer From Software's YouTube channel, here's a new trailer for Dark Souls II's three DLC episodes, to be released later this year for PS3, 360, and PC.
No word on release dates just yet, but the full pack is called "The Lost Crowns," and Japanese Dark Souls II players will get episodes in July, August, and September.