Rihanna was reportedly left "disturbed" after a male fan got to within 12ft of her as she relaxed at her Bajan holiday home.
According to the Sun, the man walked onto the star's balcony while she was lying by the pool and was then grabbed by security staff.
The fan - who was later arrested and released without charge - is said to have travelled to Rihanna's homeland in the hope of meeting the We Found Love singer, and apparently accessed the luxury property by swimming onto a beach at the rear of the building.
This weekend, Rihanna donated £1.1million to the island's Queen Elizabeth hospital in memory of her late grandmother.
The star said the donation to buy three pieces of medical equipment was her way "giving back to Barbados".
The hospital's radiotherapy unit has been renamed the Clara Braithwaite Centre for Oncology and Nuclear Medicine after Rihanna's grandmother, who died in June.
Rihanna recently released Unapologetic, her seventh album in seven years.