No, he didn't let her wear his mitre. She wore a designer outfit. But he did attend the event. Which is shameful.
Beats me. All related to the Met's big exhibition "Heavenly Bodies: Fashion and the Catholic Imagination."
https:// www.metmuseum.org/press/exhibitions/2017/heavenly-bodies
“The Catholic imagination is rooted in and sustained by artistic practice, and fashion’s embrace of sacred images, objects, and customs continues the ever-evolving relationship between art and religion,” said Daniel H. Weiss, President and CEO of The Met. “The Museum’s collection of Byzantine and western medieval art, in combination with the architecture and galleries that house these collections at The Met, provide the perfect context for these remarkable fashions.”
"The exhibition features approximately 40 ecclesiastical masterworks from the Sistine Chapel sacristy, many of which have never been seen outside the Vatican. Encompassing more than 15 papacies from the 18th to the early 21st century, these masterworks are on view in the Anna Wintour Costume Center galleries and include papal vestments and accessories, such as rings and tiaras. The last time the Vatican sent a loan of this magnitude to The Met was in 1983, for The Vatican Collections exhibition, which is the Museum’s third most-visited show."