Last year's Arc runner-up Sea Of Class has lost her battle with colic.
The daughter of Sea The Stars had been left fighting for her life after suffering a career-ending bout of the abdominal disorder, following her comeback run at Royal Ascot in the Prince Of Wales's Stakes.
Despite her stability improving in recent days, the condition sadly got the better of her on Monday morning.
One of the stars of last season, the four-year-old Sea Of Class won the Yorkshire and Irish Oaks - two Group One's before heading to Longchamp to so nearly run down Enable in the Prix de l'Arc de Triomphe.
Known for her unique hold-up style, she became accustom to saving all her speed and stamina for the closing stages under regular pilot James Doyle.
She won on four of her six starts last term before returning to the fold at Ascot in the ten furlong Group One on the Wednesday, with no one able to predict the series of events that was about to approach her.
It has left so many gutted and upset that we will never see her rematch Enable in the Arc, but more so the character and personality she brought to the sport.
Her trainer William Haggas issuing the following statement, on arguably the best filly he has ever trained.
(Credit: Racing Post) He said: "The reason for colic surgery on Sea Of Class in the first place was to remove an abdominal mass sitting between the spleen and liver which had intertwined with her gut.
"That mass was removed and some of the gut taken out. However the mass turned out to be a malignant tumour known as a lymphoma.
"Her surgeon Richard Payne and specialist Celia Marr warned us that lymphoma's can be aggressive and so it proved.
"Having made sure and steady progress under the excellent veterinary team at Rossdale's she took a turn for the worse at 4.30am this morning and a subsequent scan revealed another tumour the size of an orange.
"Despite regular scans during her convalescence, this was the first sign of an abnormality.
"She was quiet and uncomfortable today – and quite weak and the decision to put her to sleep was then taken unanimously by her team of experts, Maureen and I.
"Owner Mrs Tsui has been in full support of all decisions taken and she, her family and advisors are all devastated.
"For all of us here, we mourn the loss of the best filly we had anything to do with but will cherish the memories for ever," he finished.
Everyone at the Winners Enclosure passes on their condolences to William Haggas and his staff, jockey James Doyle and the owners.
RIP Sea Of Class.