When I was very much younger, I went to a tour performance of
Agnes de Mille's Heritage Dance Theater.
Jean Ritchie herself, with her dulcimer, came on, mid-performance,
to sing a few songs;
the dancers stood around her and sang along with her.

Afterwards I went backstage to thank Jean Ritchie in person.
An unforgettable experience.

The two songs she sang that I remember:
Going to Boston ("ear-lye in the mor-ning")
One I Love