Ambassadors
Foreign Ambassadors
Envelope (2 lines): His/Her Excellency [Full Name]
The Ambassador of [Country]
Salutation: Your Excellency, or Dear Mr./Madam Ambassador
Oral Address: Your Excellency, or Mr./Madam Ambassador
Place Card: The Ambassador of [Country]
American Ambassadors, if you are also American* (note: slightly more casual)
Envelope (2 lines): The Honorable [Full Name]
The Ambassador of the United States to [Country]
Salutation: Dear Mr/Madam Ambassador, or Dear Ambassador [Last Name]
Oral Address: Ambassador [Last Name]
Place Card: Ambassador [Last Name]
*Non US citizens call American Ambassadors "Your Excellency"
[Photo: His Excellency Sir Peter Westmacott, the Ambassador of the United Kingdom and his wife Lady Susan Westmacott]