The tennis-mad monarch, who is a regular at Wimbledon, and one of his closest pals Christian von Buchwald sat down to watch 24-time Grand Slam champion Novak Djokovic in action.
Overshadowed by President Trump's threats to seize Greenland, a Danish territory, the event removed U.S. officials from the program and saw protests arrive.
The singer, 41, put on a racy display in a series of nightwear costumes as she performed her West End Girl show at Denmark's Roskilde Festival on Saturday.