Onetime boy band member Tom Mann took to Instagram this week to mourn the loss of his partner, Danielle Hampson, whose sudden death has left him “completely broken,” he wrote. Hampson, 34, died early on Saturday, hours before the pair were set to be married, according to Mann. Her cause of death was not shared in his post. “On what was supposed to be the happiest day of our lives ended in irreversible heartbreak,” said Mann, 28, who joined Stereo Kicks after auditioning on X Factor in 2014. “I feel like I have cried an ocean. We never made it to the alter [sic]; or got to say our vows, or dance our first dance, but I know you know that you were my entire world and the best thing that has ever happened to me, Danielle.” Hampson was a PR exec and accomplished dancer who had performed with Harry Styles, the Spice Girls, and Little Mix. She and Mann shared an 8-month-old son, Bowie. “I promise you he will know how amazing his mummy was,” Mann wrote. “I promise to make you so so proud.”