Though it was our first meeting, we felt like old friends.
Tips
history
Echoes 《左传·襄公二十九年》: '见子产,如旧相识' — 'meeting Zi Chan felt like meeting an old acquaintance.' The Song source 《贾氏谭录》 tells of Prime Minister Li Bi (李泌) meeting the poet Gu Kuang (顾况) and greeting him as if they'd known each other for years.
usage
Very warm and positive. Specifically for people, not things. Compare 一见钟情 (love at first sight) — same structure, romantic feelings; 一见如故 is about friendship-level instant connection, regardless of gender or relationship type.