Sergei Polunin is one of the most talented male ballet dancers the world has ever seen. In terms of raw ability, he is on a par with Nijinsky, Nureyev and Baryshnikov - except that he's taller than the last two, and far more beautifully proportioned than Nijinsky.
He has grace, speed, power, elevation, "line", looks, and - most crucially of all - the 24-carat ability to inhabit a character. In other words, the full balletic arsenal.
Small wonder the Royal Ballet bagged him when he was just 20, making him the youngest principal that the company had ever had.
Cut to the present, however, and things are looking very bleak for the Ukrainian who, at 29, ought to be at the zenith of his career.
Only last week, it was reported that the Paris Opera Ballet had invited him to guest star in their forthcoming Swan Lake (playing Prince Siegfried as a repressed homosexual): an honour indeed.
But, in the build-up, followers of Polunin's Instagram feed noticed him showing off a new, faintly alarming tattoo of Vladimir Putin (of whom he is an admirer)and spouting some very unpleasant stuff indeed.
"Man up to all men who is doing ballet there is already ballerina on stage don't need to be two," he wrote, in his faltering English. "Man should be a man and woman should be a woman ... That's a reason you got balls. Same think outside ballet."
The rant carried on, even more angrily and nonsensically than that.
Dancers were swift to respond to this apparently homophobic tirade: "Such an embarrassment you are @SergeiPolunin - ," wrote senior Paris Opera corps member Adrien Couvez on Twitter, adding that Polunin "has nothing to do with our values of respect and tolerance".
Sure enough, Paris Opera has now revoked Polunin's offer, with Polunin's comments feeling very much like career suicide: where once he was unmissable, he is now looking unhirable.
How different this past decade ought to have been for him. Upon joining the Royal Ballet in 2003, Polunin instantly became its biggest star, blazing in roles as varied as both Solor and the Bronze Idol (in La Bayadère), Des Grieux (Manon), and Lensky (Onegin), and creating the twin role of Jack and Knave in Alice's Adventures in Wonderland.
A future as one of ballet's all-time greats was there for the taking. Barely two years later, in January 2012, Polunin suddenly quit a startled Royal Ballet, citing a need for greater artistic freedom.
Reports of a predilection for tattoos and cocaine began to circulate, along with erratic behaviour that included quitting Peter Schaufuss' new dance version of the thriller Midnight Express weeks before the curtain even went up.
Despite Polunin's slap in the Royal Ballet's face, the company's new director Kevin O'Hare generously welcomed him back in 2013 to dance with Tamara Rojo, another star who had recently left.
The work in question was Frederick Ashton's 1963 tragedy Marguerite and Armand, and he looked like the perfect dancer, someone in a luminous class of his own.
Three years later, he dropped jaws across the world - an astonishing 26,081,698 at time of writing - with his performance in David LaChapelle's online music video for the Hozier song Take Me to Church. In other words, Polunin still "had it". And a bright future - echoing, perhaps, that other brilliant Royal Ballet School alumnus who took a road less travelled, Michael Clark - still beckoned.
Then, the bubble burst.
True, Polunin secured a role in the 2017 big-screen remake of Murder on the Orient Express, but that was the high point in an otherwise worrying-looking year for him. Coming across as much petulant child as troubled genius in Steven Cantor's biopic about him, Dancer, he finally tested the Royal Ballet's patience to - and presumably way past - breaking point that same year by pulling out of two further star turns in a fresh revival of Marguerite and Armand.
And, just days after grumbling in an interview with a British glossy mag about his alma mater, he unveiled part one of his new vehicle, Project Polunin, at Sadler's Wells.
I awarded this evening a generous one star on these pages. Artistically, it was toe-curling, and not only that: Polunin already wasn't looking quite the dancer he had been.
It already seemed as if he needed the rigour of the Royal Ballet far more than the Royal Ballet needed him, and this was confirmed in December that same, awful year with the unveiling of the project's second instalment.
This scraped a second star from me only because of a sumptuous turn from his then on-off - now off - girlfriend, the Royal Ballet principal Natalia Osipova.
In other words, a professional tragedy was unfolding before one's eyes - a once-in-a-generation dancer coming from nowhere and then squandering his titanic abilities - and last week, it has reached what may well be an unrecoverable nadir.
From the start, there appears to have been considerable pressure on Polunin.
Born in 1989 in the industrial town of Kherson, in modest circumstances, he had a talent for gymnastics that was spotted early, leading to four years (from the age of 4 to 8) at a dedicated academy.
His mother, Galina, accompanied the young Sergei to Kiev, while his father, Vladimir, went to work in Portugal to provide for them.
Having switched to dance, and spent a further four years training at the Kiev State Choreographic Institute, Sergei was snapped up at 13 by the Royal Ballet Lower School.
And, just two years after the culture shock of arriving, sans a word of English, at the school his parents divorced.
Add to all this the Herculean demands of ballet - not the most forgiving of professions - and it does not require a huge leap of the imagination to understand why Polunin might have wanted to leap spectacularly off the tights-and-tutus treadmill and try the wilder side of life.
What's so sad is how poorly it now seems to be working out for him.