Christmas single.The choir, made up of nurses, doctors and other health care staff working in the British capital’s Lewisham and Greenwich public health service, joined the Canadian pop star for a special version of his song “Holy” in a bid to top the Christmas chart.Choir members recorded their vocals at London’s famous Abbey Road Studios. Profits from the collaboration will go to National Health Service charities.The choir gained fame when it vied with Bieber in 2015 for the Christmas No.