A keen footballer fell to his death in the River Thames while on Facetime to his girlfriend, who looked on horrified as the freak accident unfolded.
James East, 25, was on a night out in Kingston, London, with girlfriend Arabella Ashfield to celebrate her sister's 18th birthday but the couple became separated. They were talking on Facetime as he tried to make his way to a taxi his girlfriend was in.
But as he went to sit on a walled area of a bridge over the Thames, he misjudged its height before falling backwards and hitting his head.
He was rescued from the water after 50 minutes and rushed to hospital where medics spent three hours trying to save his life.
But it later emerged that he had already died from the head injuries suffered when he fell, his family said.
Sister Abigail Bladen said: "His poor girlfriend, Arabella, was actually on Facetime to him trying to direct him to their taxi, and she has gone through hell now as she has watched that happen.
"He was in the water for 50 minutes and then they found him and took him to hospital where they worked on him for three hours to try and save him.
"When he had the post mortem, it was found that he was dead before he entered the water due to his head injuries, but they didn't realise that.
"Because he went into the Thames they thought he had drowned. They were working on him thinking he had drowned when it was his head. They weren't to know that."
East, originally from Swansea, South Wales, had studied at the London School of Economics before falling in love with the city and just six weeks before his death had landed a dream job as a business development executive at Trybe in London.
His sister described the heartbreaking moment when South Wales Police knocked on the family's door to say what had happened.
"It was just horrendous for my mum," she said. "Kingston Police had to call South Wales Police who then had to come here at 4.50am and knock the door.
"It was a three and a half hour drive up there which was just horrendous for my mum and our stepdad. They asked them to pull over half way to say they couldn't work on him any longer and that there was nothing they could do.
"It's horrendous, just for them being on the side of the motorway and to receive that news. They tried to get a police escort, but couldn't get one, so they had to drive the rest of the way."
A keen sportsman, the 25-year-old had previously had trials to play for Leicester City and was due to run the London Marathon the week after his death.
Paying tribute to him, his sister described him as "the life and soul of the party" and said the number of people who attended his funeral on 13 October - including the bosses he had only known for six weeks - showed how popular he was.
A fundraiser has raised over £2,300 to support his family.