Lavish Engagement Bash for Heiress Stephanie Onisforou

heiress Stephanie Onisforou showed off her stunning engagement ring at a swanky party on Friday, celebrating her upcoming nuptials with Ari Kaklamanis.

Stephanie, 25, the daughter of the property and retail tycoon Theo Onisforou, announced she was set to tie the knot to the 28-year-old Million Dollar Listings entrepreneur last year.

The designer behind the bride-to-be's impressive five-carat yellow diamond rock is Sophia Paspaley, a close friend of Stephanie's and member of the Paspaley family, famed for their pearl jewellery.

The festivities celebrating Stephanie and Ari's engagement took place at the bride's family estate, Kangaloon, in the Southern Highlands of , reported The Daily Telegraph.

The exclusive guest list included Nicole Gazal O'Neil, a former cast member of The , who enjoyed a sumptuous meal featuring oyster shuckers.

The publication reports that the dessert table was supplied by 'dessert designers' Strawberry and Co. and featured a cake with a swan decoration.

Details of the décor for the event included flags flying along the estate driveway and delicate frilled umbrellas on each table.

Photos have emerged of Stephanie sporting a bespoke gown from Sydney designer Lee Matthews for her milestone event.

Ari took a more casual approach for his outfit, which included a white shirt and chinos. 

It's understood that the happy couple have been together for several years.

So far, the pair, who are famously private, have not released any details or a date for their wedding.

Stephanie, who founded the French patisserie Cafe de la Fontaine in Potts Point, is a well-known figure among Sydney's elite with powerful connections.

Her father, Theo, was the chief money man for the late media mogul Kerry Packer.

He later moved into the real estate sector, where he would make serious money acquiring and revitalising unique and neglected buildings.