AceShowbiz - %cRihanna% joined the Flintstones-themed birthday party of her cousin Noella Alstrom's daughter Majesty on June 7. Doing her best to make her 1-year-old niece's special day the best, the "American Oxygen" singer sizzled in an orange-and-black costume as she introduced herself as "Thotty Pebbles."
Rihanna looked irresistible as she sported the asymmetrical off-the-shoulder outfit which showed off her toned midriff. Accessorizing her look with bones, the "Diamond" singer looked similar to toddler character Pebbles on the popular Hanna-Barbera cartoon.
The Grammy-winning star attended the bash along with some pals including Jennifer Rosales, who dressed up as "Ratchet Wilma," and Melissa Forde. The lively event was documented by Melissa in several videos which were later uploaded on her Instagram account.
In one video, Rihanna is seen dancing to the music with Jennifer who shows off her hilarious moves.
Another adorable clip features partygoers singing "Happy Birthday" to Majesty as she checks out the colorful three-tiered cake while being held on her mom's arms.
Rihanna is seen dancing alongside Melissa to hits played by DJ Spade at the backyard filled with balloons in the shape of the birthday toddler's name and party decoration in another video.