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LONDON -- What made the ballet dancer jump? The dance world is spinning after one of ballet's brightest stars walked away from Britain's prestigious Royal Ballet without explanation, days before he was due to take the lead in a new production.

Ukrainian dancer Sergei Polunin announced this week that he is quitting immediately. He had been due to open as Oberon in "The Dream" next week.

The 21-year-old studied dance in Kiev before attending the Royal Ballet School in London from the age of 13.

He has thrilled audiences since he became the company's youngest-ever male principal dancer at the age of 19. His poise, muscularity and gravity-defying leaps have brought comparisons with the young Rudolf Nureyev and Mikhail Baryshnikov.

Royal Ballet director Monica Mason said Polunin's resignation had "come as a huge shock."
"Sergei is a wonderful dancer and I have enjoyed watching him tremendously, both on stage and in the studio, over the past few years," she said in a statement. "I wish him every success in the future."

Ballet websites swirled with speculation about the motive for Polunin's sudden departure. Some suggested the dancer -- who co-owns a London tattoo parlor -- might have grown frustrated with the strict discipline of the ballet life.

In an interview last year, he referred to the pressure he felt to succeed.

"I would have liked to behave badly, to play football. I loved sport," he told The Guardian. "But all my family were working for me to succeed. My mother had moved to Kiev to be with me. There was no chance of me failing."

Others speculated Polunin might have been poached by a rival company. His Twitter biography on Thursday read "principal dancer of ?"

Emilia Spitz, of dance blog TheBalletBag, said that if Polunin had been offered a more tempting contract, no company had yet come forward to admit it.

Spitz said Polunin might be symptomatic of a growing trend for dancers to seek more control over their careers than allowed by the hierarchies of established classical companies.

"These young people are evolving in that they are really taking control of their careers," she said. "It's a case of ballet contracts becoming a bit more like football contracts."

And Tony Hall, chief executive of the Royal Opera House -- home of the Royal Ballet -- appeared to leave the door open to a return.

"I think we've just got to support him -- he deserves that -- through his thinking at the moment about his life," Hall told Channel 4 News. "The pressures on him are of course enormous."
Attempts to reach Polunin at the tattoo parlor were unsuccessful