At the Tokyo Game Show in 2011, Square Enix revealed they were working on an HD version of Final Fantasy X for PlayStation 3 and Vita.
After a long silence about the project, during a February 2013 PlayStation Vita presentation in Japan, they showed updated character models from Final Fantasy X running on a PlayStation Vita.
Not long after that, on March 19th, 2013, it was revealed in Jump Magazine, that the PlayStation 3 version, would actually be an HD Collection containing Final Fantasy X and its sequel Final Fantasy X-2. It was also announced that the ports are based on International Version and the International + Last Mission Version respectively.
Both titles would also still come to Vita, but as separate releases. This is due to cartridge size on the Vita not being large enough to support both titles. On the bright side, both the Vita & PS3 versions will support cross-save functionality.
During PAX East 2013, Square Enix not only confirmed that both games would be getting an HD upgrade and would be bundled together on PS3, but they also confirmed that the collection would be available worldwide. This will mark the first time Final Fantasy X's International Version will be available in North America, and the first time Final Fantasy X-2's International Version will be available in regions outside of Japan.
It was more recently reported, that the developers are adding a brand new 30 minute ending/epilogue, that will play during the credits of the compilation. It will talk place one year after Final Fantasy X-2 and will feature new characters, but whether it is playable or just a cutscene is unknown at this time. That said, in addition to it being in the PS3 collection, this new ending will be in included in the Vita version of Final Fantasy X-2 as well.
Like Kingdom Hearts HD 1.5 Remix, fans who pre-order Final Fantasy X/X-2 HD Remaster on PS3 will receive a 24-page art book with concept art and commentary from the developers of the two games.