Magician David Blaine is to be suspended from a crane in a Perspex box at Potters Fields near Tower Bridge without food for 44 days for his next feat of endurance.
Sky One and Channel 4 are both to screen the event, entitled David Blaine: Above the Below which kicks off on Friday 5 September.
He will live in a box, just seven feet by seven feet deep by three feet and plans to stay there for more than six weeks.
He will have no food, communication or any distractions. His only source of nourishment will be a tube feeding him water and another tube for urination.
Past stunts have included standing on a 100ft high pole in New York for 35 hours and encasing himself in six tons of ice for three days.
Blaine, who has a third eye tattooed on his palm, said: "There will be no trickery and no means of escape.
"We are all capable of infinitely more than we believe. We are stronger and more resourceful than we know, and we can endure much more than we think we can. In truth, the only restrictions on our capacity to astonish ourselves and each other are imposed by our own minds.
"My next performance will demonstrate these ideas through the most extreme exercise in isolation and physical deprivation ever attempted."
Sky One will show him going into the box live on Friday 5 September at 8pm, with Channel 4 showing the footage three days later at 10pm.
If he stays the course his exit will be shown live on Sky One on Sunday 19 October at 9pm and screened by Channel 4 on Monday 20 October at 10pm.
Sky One will show continuous coverage of the event on its interactive service (press red on Digital Satellite), while Channel 4 will provide a live stream on its website at www.channel4.com/davidblaine
During his time in London, Blaine will also be unleashing his ‘street magic' on the British public, in a series of settings including Lambeth and the London Eye. This will air as part of the Above The Below programmes, both screened on Sky One and Channel 4.