The 28-year-old illusionist, Steven Frayne, made it half way across the river, with the Houses of Parliament providing a stunning backdrop, as he was scooped up by what appeared to be a police boat yesterday.
The stunt was part of a promotion for the magician's new TV show.
Onlookers clamoured for viewing spots on the banks of the famous river and along its bridges as the Bradford-born trickster, known as Dynamo, slowly made his way across the water.
Sceptical spectators and viewers online have suggested that Frayne was walking along a cord or platform submerged slightly underwater.
A YouTube video shows Frayne sizing up the water before stepping in and some users commented that he was looking for something in the water before taking his first step.
Frayne has earned a reputation for himself in recent years and has played prankster to a host of the rich and famous including Jay Z, Robbie Williams and Natalie Imbruglia.