Swiss hedge fund manager Arpad Busson and actress Uma Thurman are engaged to marry, according to published reports.

The two began dating last year, and Busson proposed to Thurman during former South African President Nelson Mandela’s 90th birthday celebration in London with an enormous diamond ring, reportedly in excess of 8 karats with 20 smaller surrounding stones. The engagement was announced in The Times of London.

The old-fashioned wedding announcement, headlined “Mr. A. Busson and Miss U. Thurman” read, “The engagement is announced between Arpad, son of Mr. Pascal Busson, of Paris, and Mrs. Florence Harcourt-Smith of South of France, and Uma, daughter of Mr. and Mrs. Robert A.F. Thurman, of New York.”

Busson, a 45-year-old Swiss millionaire who is chairman of US$15 billion hedge fund EIM SA, was formerly engaged to supermodel Elle Macpherson, with whom he has two sons. He would be Thurman’s third husband, and the first non-actor with whom she ties the knot. The 38-year-old previously was married to Gary Oldman and Ethan Hawke.