Earl Spencer, the younger brother of Diana, Princess of Wales, has announced his engagement to a Canadian philanthropist.
Prince William and Harry's 46-year-old uncle and Karen Gordon, 37, will tie the knot at the Spencer family home, Althorp, in Northamptonshire on June 18.
A spokesman for the couple said it would be a "private ceremony" attended only by close family and friends.
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Bride-to-be Karen is a former model and mother-of-two who was previously married to Mark Gordon – a millionaire film producer, whose credits include Saving Private Ryan and TV series Grey's Anatomy.
Following their split, she used her divorce settlement to establish her own charity, Whole Child International, to help improve the care of children in orphanages and other institutions.
It is thought that twice-divorced Earl and Karen started dating at the end of last year. They fell in love after he split from former fiancée Lady Bianca Eliot in September 2010 after two years together.
The British peer – worth an estimated £120 million - has had a tangled personal life. He was married to Victoria Lockwood, with whom he has four children – Kitty, 20, Eliza, 18, Amelia, 18, and Louis, 16 - from 1989 until December 1997.
He wed his second wife Caroline Freud in 2001 and they welcomed a son Edmund, seven, and a daughter Lara, who is four.
But in 2006, when their youngest was six months old, the Earl left her and began seeing American reporter Coleen Sullivan. That relationship lasted 18 months.
Then, in March 2010, he announced his intention to wed widow Lady Eliot but called off the engagement six months later.