The pop star was recording a video for her song, "We Found Love" on a farm near Belfast when she removed her dress, stripped down to a bikini and then went topless.
The farmer, Alan Graham, jumped off his tractor and told the crew to stop the music. They complied.
Graham said he and his wife are Christians and found the sexy singer's behavior "inappropriate."
Rihanna and Graham shook hands, and the singer and her crew moved on.