Her usual risqué outfits just wouldn't cut it for the occasion – especially since she was joined on the night out by her mum Monica Fenty and grandfather Lionel Braithwaite.
The 24-year-old singer is extremely close to the pair, particularly as she has something of a rocky relationship with her father Ronald Fenty.
Her parents' turbulent marriage broke down when Rihanna was 14 amidst her father's long struggles with drug addiction.
But although the singer doesn't see her dad that often, she likes to keep her mum close – even if she has a habit of embarrassing her.
The Rude Boy singer told her Twitter fans how Monica had made a joke about Ashton Kutcher, who Rihanna was rumoured to be dating.
"Well....2nt consisted of us singing Bob Marley, drinkin Vintage Scotch, and my mom thinkin a joke abt Kutcher was appropriate!" she wrote.
Rihanna was being honoured as one of Time's list of most influential people.
Others at the gala, at which she performed, included Hilary Clinton, Oscar winner Tilda Swinton, Homeland star Claire Danes and Bridesmaids actress Kristen Wiig.