Princes William and Harry are set to reunite as they will both take part in a ceremony paying tribute to their late mother, Princess Diana, at the Diana Legacy Award. William, Prince of Wales, 41, will attend the event at the Science Museum in London on Thursday night in person, where he is expected to give a speech to mark the charity’s 25th anniversary and present awards to 20 recipients. William's estranged brother Prince Harry, Duke of Sussex, 39, will then join a video call with the winners, according to reports.