'R.I.P' Singer Rita Ora -- COLLAPSES During Photo Shoot

British pop singer Rita Ora -- who had the hit song, "R.I.P." -- collapsed on the set of her photo shoot in Miami Beach today ... and was rushed to a hospital by ambulance according to photographers on the scene.

Photos show the 22-year old singer/model/actress -- eyes closed -- being unloaded from the ambulance on a stretcher ... attended by emergency personnel. So far, no word on what may have caused her to collapse.

Ora -- who famously dated Rob Kardashian last year -- was reportedly preparing for her photo shoot on the beach near the SoHo Beach House hotel when she fainted in her makeup trailer.

We've reached out to Rita's people -- so far, no word back.

2:01 PM PT Ora's doctor, David Farcy, tells TMZ Rita was treated for heat exhaustion and dehydration. She's been discharged and Dr. Farcy says she's fine. She flashed a big smile to fans when she returned to her hotel from the hospital. Rita was in the middle of a photo shoot for Madonna's Material Girl campaign in Miami when she was taken ill.