[Shaun]

from TMZ, and more importantly, Harry's twitter

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 loaded into 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.

must be sun depravation from being in Rihanna's shadow so often