The 27-year-old Barbadian beauty could not have looked more regal in the low-cut vintage Christian Dior dress, complimented by a dazzling, jewel-encrusted necklace.
Rihanna pulled out all the stops for the star-studded charity gala, which supports the Clara Lionel Foundation -- an organization she founded in 2012 in honor of her grandparents, Clara and Lionel Brathwaite -- that works to improve the quality of life for underprivileged communities across the globe.
Rihanna spoke with ET’s Kevin Frazier on the red carpet, where she opened up about her grandmother, who died of cancer in 2012.
"She is definitely here in spirit and she feels delighted to be a part of such a great cause, raising money in her honor, to help, save and change many lives," Rihanna said.
The "Diamonds" singer also took the opportunity to make Majesty -- the 18-month-old daughter of Rihanna's cousin, Noella Alstrom -- feel like a superstar.
Rihanna pulled out all the stops for the star-studded charity gala this year after the first annual Diamond Ball generated over $2 million in donations.
The charitable proceeds were used to renovate and transform the Queen Elizabeth Hospital in Barbados "into the most modern cancer treatment facility in the Caribbean," she recently told ET before the night of the big event. "I am beyond proud of the work the Clara Lionel Foundation has done."