In a very formal setting how would you greet and thank the host for being invited to a social gathering?

Question

Was invited to a private home with diplomatic and military personnel present.

Answer 1

I would say either "Buenos días" (daytime) or "Buenas tardes" (afternoon) or "Buenas noches" (nighttime). To thank you would say "Muchas gracias por invitarme."

Answer 2

HI hwakins, welcome

Hmmm, I think a straightforward:

Les agradezco la invitación. Nos sentimos honrados.

I think that would be ok, let's see if somebody else has any other idea.