Historian Daniel J. Boorstin once defined a celebrity as someone who is "known for his well-knownness" — a person famous for being famous. Though many celebrities have talent and other attributes that draw attention, it is easier to gain notoriety passively by being related to someone who already has some. Children of celebrities are automatically celebrities, meaning they don't have to do any work to earn that status, though they may have to work to maintain it.
She is called an actress whenever she is introduced, but Mika Mifune is mainly famous for being a daughter and a wife — the child of the late movie actor Toshiro Mifune, and the spouse of rock singer George Takahashi. With regard to the former, Mifune's celebrity was made more compelling by the fact that she was born out-of-wedlock to her father's mistress. It wasn't until he wrote his will that he acknowledged her legally as his offspring. She took his name and became the object of media scrutiny, so much so that she had an agent by the time she was in junior high school.
Takahashi met her when she was 13. He says it was love at first sight. Twenty-four years her senior, he waited until she was 16 before popping the question and they married almost immediately. So now Mifune had two celebrity referents: a deceased father who starred in some of the greatest Japanese movies of all time, and a musician husband who was old enough to be her father. The second referent quickly became more important than the first as the couple turned into a media item, appearing on variety and talk shows together as the epitome of the "sweet couple," partners whose marriage was based on love rather than convenience. They were twice named Best Couple of the Year by whatever commercial enterprise happened to be giving out such awards at the time.