William's uncle, Charles Spencer, 46, is engaged to Karen Gordon, according to an announcement from Spencer's rep.
"Charles, the ninth Earl Spencer, is delighted to announce his engagement to Karen Gordon, a Canadian philanthropist who is the Founder and CEO of Whole Child International," said the official statement.
The private wedding will take place on June 18 at Althorp in England, the ancestral home of the Spencer Family, the statement also said.
Spencer, the brother of the late Princess Diana, is remembered for his controversial – given how it addressed his sister's treatment by the royal family – eulogy he delivered at her funeral service in 1997.
It will be Spencer's third marriage. He has four children from his first marriage and two children from his second.