Audrey Hepburn
Oh, Audrey, say it ain't so! According to a former White House secretary, Hepburn visited Kennedy when he was a young senator, right after she had won an Oscar for Roman Holiday. This was 1953, the same year he married Jackie (so, unclear whether or not she was an actual homewrecker, though he had met Jackie back in 1952). Audrey stans may also remember a little known fact about the star: she actually sang "Happy Birthday" to the prez a year after Monroe's famous rendition, 10 years after their short-lived romance.