The chosen 100 will take part in a "daring display of aerial acrobatics comparable with the greatest circus performances in the world". And what's more, no experience is necessary.
They must be more than 16 years of age, strong, agile and with a head for heights - the Dome reaches up to 150 feet.
"We're going to be training these people to fly through the air and catch their colleagues, so they need to have some kind of spatial awareness as well," said a spokesman.
The show is being put together by Mark Fisher, who has designed productions for the Rolling Stones, Tina Turner, REM and Janet Jackson.
Circus performers can audition, but the organisers are keen to train as many as they can from scratch.
The 20-minute show, which will run six times a day, will play to audiences of up to 12,000.
The hotline - 0800 665499 - was opened on the day the sex of the 320- foot tall giant, which forms the centrepiece of the Dome was revealed.
Millennium chiefs have agonised over whether the figure should be male or female, but revised designs show they have reached a bizarre compromise - a creature half man, half woman. One side of the figure has a contoured breast, the other sports pectorals.
A spokesman for the New Millennium Experience Company said: "You can tell which side is male and which is female from the posture and the muscles. There's no giant genitalia or anything like that."
Instead the private parts of each will be "smoothed over" in the style of "swimsuit decency". In addition, the figure will now be reclining instead of seated.
Visitors will still enter the figure through the leg and exit at the lower back.
Designers claimed the changes were determined by the demands of "traffic flow" around the figure.