A collaboration between Bravely Default: Flying Fairy and Fantasy Earth: Zero has been in the works. According to various sources, the collaboration involves job classes and characters from Bravely Default making a cameo in the PC RPG.
The first steps of development happened during an event in July. The event was the Fantasy Earth: Zero offline event titled Melfaria Thanksgiving Event 2012.
A teaser site has been revealed showing the jobs and how the crossover would look with the jobs and characters appearing in the art style. The date of October 22 was given as the start of the project with the words, “Collaboration Start.”
Bravely Default: Flying Fairy is a JRPG recently released for the Nintendo 3DS in Japan on October 11, 2012. Fantasy Earth: Zero is a MMORPG developed for the PC. It was first released in 2006 and has seen multiple releases across regions. Both games were made and handled by both Gamepot and Square Enix.
Source: Dengeki (http://news NULL.dengeki NULL.com/elem/000/000/546/546542/), Fezero (http://www NULL.fezero NULL.jp/collaboration/bravelydefault/)