The 'Umbrella' singer is reportedly engaged to Chris Brown of the 'Run It!' fame.
Friends close to the couple say that when 19-year-old Brown popped the question over the New Year 20-year-old Rihanna agreed to the proposal.
The singer showed off the ring while she was performing in London, the Sun reported.
Despite the cold, she wore fingerless gloves and held her hand to her chest so people could clock the rock.
"Rihanna was wearing the biggest diamond you can imagine," a source said.