My Dream Boat has caused a major upset in the Prince Of Wales's Stakes, giving trainer Clive Cox and jockey Adam Kirby a second Group One win at Royal Ascot.

Beaten a long way by Japanese superstar A Shin Hikari in France last time out, My Dream Boat was the 16-1 outsider of the seven-runner field on Wednesday (Thursday (AEST).

Yutaka Take on odds-on favourite A Shin Hikari, the highest-rated Flat horse in the world, was sending out distress signals soon after turning for home.

Ryan Moore then produced Found and looked sure to give Aidan O'Brien his 50th Royal Ascot winner, but Kirby was just starting his run on My Dream Boat.

The four-year-old even defied a drift into the centre of the track to beat Found by a neck.

Kirby became a father for the first time on Tuesday when his girlfriend Megan Evans gave birth to a boy while he was at Ascot to ride Profitable to win the King's Stand Stakes.

"This week has proved if you get the chance you can deliver them. It's been a great week and I hope Mum and Megan are watching," Kirby said.

"It's great having a newborn and it's been an unbelievable week.

"I saw my son for the first time last night and it's indescribable."

Cox said although My Dream Boat was soundly beaten in France he was confident he had him right for Ascot.

"I was full of admiration for the Japanese horse in France when we took him on," he said.

"We knew we didn't quite run our race. He's found a perfect rhythm today and really found when Adam got into him and asked him to stretch.

"Any horse that comes home after a race like he had in France we nurture them back to run with confidence.

"After being beaten last time, he's not surprised me, but his upward curve has been phenomenal and we got it right today."

Connections of A Shin Hikari were understandably deflated.

Hirotsugu Hirai, spokesman for owners Eishindo Co Ltd, said the soft track did not suit the horse.

"We knew it was not going to be easy," he said.

"It was his first time round a bend this sharp and it was a surprise to him.

"Also, the turf was very soft - like a luxurious carpet - and that didn't suit him.

"After the race the horse was fine, but we are upset."