Anthony Van Dyck has been euthanised after breaking down in the Melbourne Cup.
The horse was one of the favourites heading into the race but went lame on the home straight.
Jockey Hugh Bowman immediately dismounted and Anthony Van Dyck's strapper ran out onto the track to be with him as an ambulance arrived.
Racing Victoria's Executive General Manager of Integrity Services, Jamie Stier, confirmed the tragic death in a statement after the race.
"It is with sadness that we confirm that Anthony Van Dyck had to be humanely euthanised after sustaining a fractured fetlock during the running of the Melbourne Cup at Flemington," Stier said.
"The horse received immediate veterinary care, however he was unable to be saved due to the nature of the injury sustained.
"Our sympathies are extended to the owners of Anthony Van Dyck, trainer Aidan O'Brien and all his staff who cared for the horse and are greatly saddened by their loss."
Simon Clare tweeted: "Poor Anthony Van Dyck. That was tough to watch."
Greens senator Mehreen Faruqi wrote: "Horrific news ... This is why we say 'nup' to the cup."
It comes after Rostropovich suffered a stress fracture to his pelvis in last year's Melbourne Cup. Fortunately, he made a full recovery.
Anthony Van Dyck is the seventh horse to die on Melbourne Cup day since 2013 and there has been a huge social media push against this year's race, with the hashtag #NupToTheCup quickly trending.
Two years ago the Cup was rocked by the death of Cliffsofmoher — who was euthanised in front of the grandstand crowd after the horse broke its shoulder. Both Cliffsofmoher and Anthony Van Dyck were trained by Aidan O'Brien.
That followed these deaths in Melbourne Cup day races:
In 2013, Verema was euthanised after snapping a bone in her leg.
In 2014, Admire Rakti collapsed and died in his stall after a race and Araldo broke a leg and was euthanised.
In 2015, Red Cadeaux broke his left foreleg, was rushed to the vet for surgery and was euthanised some days later.
In 2016, Regal Monarch died after a dramatic mid-race fall.