Here is the art with the themesong:

IMDB describe the series as "An anthology comedy series featuring a line up of different celebrity guest stars appearing in anywhere from one, two, three, and four short stories or vignettes within an hour about versions of love and romance." (1969–1974)

Regulars and guest stars are listed there. Love American Style on IMDB

Original notes on facebook, tying it in with The Love Boat, Happy Days...