Beyonce and Jay-Z’s daughter Blue Ivy Carter is secretly an exceptional pianist. Her grandmother, Tina Knowles, is “really proud” of her 12-year-old granddaughter and cannot wait until she shares her musical talents with the world. She told E! News of Blue Ivy’s hidden talent: “She’s self-taught and she sounds like a concert pianist. “She paints, she draws, she does poetry. She’s just an artistic soul.” She gushed: “I’m really, really proud of her. I can’t wait ’til the world gets to really hear.” Blue Ivy is also a dancer and was part of the backup troupe for her superstar mom on her ‘Renaiss…