Former US Senator Richard Lugar is being knighted on orders from the Queen of England, joining a select list of Americans to receive the distinction.
The Indiana Republican, who left the Senate earlier this year, will receive the rank of honorary Knight Commander of the Most Excellent Order of the British Empire during a ceremony at the British Embassy in Washington on Tuesday.
The British Ambassador, Sir Peter Westmacott, is set to preside.
Lugar will not be known as "sir" Lugar - only royal subjects can carry that title.
But few Americans have received honorary knighthood, including Presidents Dwight Eisenhower, Ronald Reagan and George H W Bush.
Lugar says he was first inspired by Queen Elizabeth's leadership when he visited England as a Rhodes Scholar and she asked him about Indiana.
