Guinness heiress Honor Uloth, 19, died in a swimming pool accident during a summer barbecue at her family home, an inquest has heard.
The teenager died six days after being found at the bottom of the pool at her family's £3.5million mansion which overlooks Chichester Harbour, in Sussex, on 31 July.
They had been hosting a barbecue at the property for four other families when the tragedy happened, Daily Mail reported.
The death of Miss Uloth, who was the daughter of Rupert Uloth and Lady Louisa Jane Guinness, was ruled an accident this week at an inquest at Crawley Coroner’s Court.
He family said: "We have lost a daughter and sister who brought untold light and joy into our lives.
"She was so full of fun, laughter, kindness and adventure.
“She had this knack of bringing people together and making them feel good."
Miss Uloth’s brother Rufus, 15, had pulled her out the pool after spotting she was unconscious, the inquest heard.
She had got into the pool by herself at approximately 11pm after spending time in a hot tub with two friends.
A total of 19 people were said to have attended the barbecue.
Coroner’s officer Geoff Charnock told the hearing: "A short while later, Honor’s brother was walking back towards the hot tub…and saw her lying at the bottom of the pool.
"He raised the alarm and rescued her from the pool. The adults commenced CPR while an ambulance was called."
She was rushed to hospital but died on 6 August after suffering brain injuries and a broken shoulder.
Mr Charnock added a police investigation did not reveal how she came to be lying at the bottom of the pool and they had been no witnesses to the accident.
Police theorized she may have hit her head when she jumped off a rock or slipped on a wet surface.
Senior Coroner Penelope Schofield recorded her death as an accident.
Miss Uloth family said in a statement: "Her last day was spent riding polo ponies in the morning, seeing friends on the beach in the afternoon and enjoying an evening with close friends and family over a delicious al fresco supper.
"It was her perfect kind of day."
The teenager was the eldest of three children and her family have a combined worth of approximately £906million.