Denmark's King Frederik X will travel to his nation's second Euro 2024 match against England in Frankfurt on Thursday, a royal statement said.
The 55-year-old will be joined by Britain's Prince William in the stands.
Denmark drew 1-1 with Slovenia in their opening Group C game while England beat Serbia 1-0.
The Danes, 1992 champions, lost to England 2-1 in the Euro semi-final three years ago.