The guests assembled from the worlds of entertainment, fashion and art and charity, and from Don’s native Co Kerry village of Ballyheigue.
Known as “the Don of Irish fashion”, Mr O’Neill began life as a chef but switched to art college, and has designed for the stars from his New York base and is creative director of Theia.
Pascal Guillermie, from Paris, is a sought-after florist in New York with his shop Fleur de Pascal and the pair reside in Brooklyn.
Close friend, stylist and event organiser Orla Diffly was among the 200 guests and said it was “a wonderful occasion filled with so much love and light and life.”
Don and Pascal designed their own outfits — duck egg blue grey with rich embroidery of sea horses and Celtic motifs.
Among the guests were singer and senator Frances Black, the Seoige sisters Gráinne and Síle; the artist Pauline Bewick, the charity worker Adi Roche and RTÉ presenter Mary Kennedy.
The party was held at Ballyheigue golf club in a marquee overlooking the sea.