Diamond Star Halo by Tiffany Murray
Growing up in a rural recording studio, Halo Llewellyn is rarely star-struck, but when one of the visiting singers gives birth to Fred, she knows right away that he's special. As the golden child grows into the gilded man, she remains dazzled by his ambition and his talent. Up on stage, being screamed at by hundreds of teenage girls, Fred will always turn his spotlight on Halo in the crowd. But that's the problem with falling in love with your charismatic almost-brother - it can never be a secret. In the end, the whole world has to know.