Strictly Come Dancing head judge Shirley Ballas is reuniting with former pro AJ Pritchard for a very special reason.AJ, who quit the dancing reality competition earlier this year, has signed up along with Love Island star brother Curtis Pritchard to join Ballas for the BBC's all-star salute to the NHS.Dear NHS Superstars is set to air later this year, as some of the biggest names in TV and film pay tribute to the NHS workers on the frontlines of the COVID-19 fight.Along with the trio already