The American businesswoman hired the then-teenager to look after her children in 1980.
Before she became “The People’s Princess,” Diana Spencer worked as a nanny making just $5 an hour.
In 1980, Mary Robertson was an American businesswoman living in London and needed a part-time nanny for her toddler son, Patrick. She called a local agency and they sent over Diana, who was just 18.
Robertson said she “fell in love with her."
Diana would do laundry, pick up toys and wash dishes, she recalled. "She was wonderful with my child," she said.
The businesswoman had no idea the shy and quiet teenager she hired was actually Lady Diana Spencer, an aristocrat from one of England’s oldest families.
But a deposit slip from Diana’s bank that she found under her couch became the clue that tipped her off.
"It said 'Lady Diana Spencer' and it was deposited to Coutts and Company, and because I worked in finance I knew that Coutts was the bank of the aristocracy and the Royal family," she said.
When Lady Diana learned her cover was blown, she reacted as if it was no big deal and simply asked to take Patrick out for a walk.
Diana worked three days a week for Robertson and was nursery school teacher the rest of the week.
Robertson got another shock a few months later when she found out Diana was dating the future King of England.
"She said, 'When you leave for work this morning, there are reporters and photographers at the end of the street.' I asked, 'Who are they there for?' She said, 'They are there for me,'" Robertson recalled.
Diana soon gave her notice that she was leaving Robertson. The next time Robertson saw her former nanny, she was walking down the aisle in the Royal wedding watched by the whole world.
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Robertson thought her relationship with Diana was over, but they remained in touch.
"We continued a correspondence for the next 16 years," she said.
Diana sent dozens of cards and letters to her former boss over the years.
"She asked for us to come and visit and I didn't read the calls to visit as little cries for help," she said.
Robertson was among the mourners at Diana’s funeral at London’s Westminster Abbey in 1997.
"Being at the funeral was probably the saddest, most painful hour I have ever spent in my life," she said.
Robertson says she will always cherish those long ago days when Diana was her nanny.
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