I don't think you need a DS3. The reason you probably heard that is because Sony has only shown PS now being played on Vita or with a DS3. Also the DS3 doesn't work with the PS4. But the controls might be formatted as if it's a ps3 controller.
I don't know as much but there was an article on ign that Sony stated if you want to use ps now on a tv you needed a ds3 maybe I'm not remembering exactly right or maybe they have it currently working with ds3 and are working to set up ds4 support