Happy Birthday, Beyoncé!. Beyoncé Giselle Knowles turns 41 years old this year. . Here are five fun facts about Queen Bey. . 1. Her favorite number is 4. 2. She was a member of her childhood group, Girls Tyme, before becoming a member of Destiny’s Child. 3. Her alter-ego is Sasha Fierce. 4. “Bootylicious” was added to the Oxford English Dictionary after the Destiny’s Child song became a huge hit. 5. Her fifth studio album, 'Beyoncé,' was the fastest-selling album in iTunes history. Happy Birthday, Beyoncé!