Sword Art Online: Lost Song‘s content will see a Julius outfit available for Kirito whilst Asuna will have an Alisa outfit made available for her.
God Eater 2: Rage Burst‘s DLC will see Gun Gale Online-style Kirito and Sinon costumes for your character.
The two sets of content are planned to release this Spring, with a possibility that they may debut at a Dengeki Online event schedule for March 15th. It would also appear that there could be more to the collaboration that is not restricted to within the game.
Also revealed in Famitsu was the news that Agil will be a playable character in Sword Art Online: Lost Song. The game will also feature Eugene and Recon, but they will not be playable in the game.
God Eater 2: Rage Burst is set to launch in Japan on February 19th, whilst Sword Art Online: Lost Song is due to release on March 26th. Neither title has been confirmed for Western localisation as of yet but be sure to keep an eye on The Vita Lounge for all the news you will need regarding these two titles!