Saudi judoka Wojdan Shaherkani was on Thursday banned from wearing the hijab head scarf when she is fighting at the Olympic Games.
The 18-year-old heavyweight, part of a two-woman team sent from the kingdom to an Olympics for the first time, was ordered by International Judo Federation president Marius Vizer to step onto the mat with her head uncovered.
"The Saudi Arabian athlete will take part in judo and she will fight according to the principle and spirit of judo, so without a hijab," said Vizer following Thursday's draw.
Judo applies strict safety rules and any covering on the head is deemed to present a risk to the fighter's health.
Shaherkani is due to take part in the women's judo competition on August 3.
Saudi Arabia only agreed to send a women's team to London on condition that their two athletes respect a strict dress code.
The country's most senior sports official Prince Nawaf bin Faisal had told local daily Al-Jazirah the two athletes would be allowed to compete as long as they will be "wearing suitable clothing that complies with Shariah."
Additionally he added other stipulations that: "the athlete's guardian agrees and attends with her," and "there must also be no mixing with men during the Games".
Men and women share the judo training venue, warm-up area in the competition hall and fight side-by-side on the various mat areas inside the competition arena.
American-raised 800m runner Sarah Attar is the second woman in the Saudi squad in London.
She has spent little time in the Islamic kingdom and grew up mostly in California, where she took up cross country running.
Attar appears without a headscarf in her official London 2012 photo.
For Shaherkani her participation is also contentious on other safety grounds as she has only been involved in the sport for two years and is not even a black belt.
That means she very likely is nowhere near the level of the international fighters she will be coming up against.
She will fight Puerto Rico's Melissa Mojica, ranked 13 in the world, in the first round.