This article written March 2013 by Will Johnson, wjhonson@aol.com, Professional Genealogist
How were Princess Diana and Sarah Ferguson related through proximity?
Proximity relationship uses not just blood, but also marriage and can go sideways through trees, not just up and down.
The easiest way to get from Diana to Sarah is through their husbands.
Diana married Prince Charles, Charles is the brother of Andrew, and he married Sarah.
So three steps.
But there is a slightly more obscure way to make the connection.
Diana's sister is Jane, Jane married Robert Fellowes, his mother is Jane Ferguson, her brother is Andrew Ferguson, his son is Ronald Ferguson, and his daughter is Sarah Ferguson. So six steps for this one.