principal photography began on october 2, 2017, in philadelphia, following a week of rehearsals, with plans for a thirty-nine–day shoot. on october 31, 2017, it was reported that shyamalan would be filming at allentown state hospital for a few weeks. on december 12, 2017, shyamalan revealed that four scenes would be shot in january 2018, stating he would have to travel for their filming.