The 24-year-old 'We Found Love' hitmaker is devastated after her death, reported Daily Mail online.
"Goodbye grangranDolly get your beauty rest until I see you...Grangran Dolly that is all," Rihanna posted on Twitter.
The singer knew her grandmother was nearing death, so she made frequent trips to New York, to spend time with her.
Rihanna posted a series of intimate pictures of her grandmother and herself, an image showed 'Dolly' wearing a baseball cap, while another, a black and white photo, revealed a touching scene of the pop superstar holding the old woman's hands.
Condolences from fellow celebrities have poured out including the one from her ex-boyfriend Chris Brown.
"Praying for family and the lost loved one. She was like my grandmother. Love you GRAN GRAN! RIP," Brown wrote on Twitter.