Jill St. John is an American actress. She is perhaps best known for her role as Bond girl Tiffany Case in Diamonds Are Forever. St. John was…Jill St. John is an American actress. She is perhaps best known for her role as Bond girl Tiffany Case in Diamonds Are Forever. St. John was born Jill Arlyn Oppenheim in Los Angeles, California, the daughter of Betty and Edward Oppenheim, a prosperous restaurant owner. As a young girl, St. John was a member of the Children's Ballet Company with Natalie Wood and Stefanie Powers. She attended Powers Professional School and received her high school diploma from Hollywood Professional School in the spring of 1955 at age 14. At 15, St. John enrolled at UCLA's Extension School.