The Star-Spangled Banner looked more starry than usual during one of US Vice President Mike Pence's appearances in Brussels.
A background picture of the American flag that went up alongside the European Union flag as Mr Pence and European Council president Donald Tusk spoke on Monday had 51 stars instead of the usual 50, one for each state.
The Brussels version of the flag had three rows of nine stars and three rows with eight stars each.
American flags typically feature a total of nine alternating rows of five or six stars.
The EU flag featuring 12 stars in a circle against a blue background was configured correctly.
And the American flag had the right number of stripes - 13.
The EU Council did not immediately respond when asked about the error.