The 26-year-old, who won the ITV talent competition last year, returned to perform some illusions for the audience shortly before the results of the fourth live semi-final were announced.
As part of his act, the soldier asked judge Alesha Dixon to choose a number at random, leading her to say: "333".
He also revealed that he had collected cards from the audience at the start of the show with their names and where they lived written on them, which he had placed in a box.
Then he threw a foam brick into the crowd and asked the woman who caught it some questions.
After his brief conversation with the audience member, Richard threw the box of the cards in the air and caught one on the end of his sword.
It turned out that the card belonged to the woman who had caught the brick and had the number 333 on it – the same one Alesha, had picked out.
Richard Jones returns to Britain's Got Talent with a new trick
Richard Jones picks the right card on Britain's Got Talent
Oh come off it, they prepared a separate set of tickets backstage and slipped it into his hands
Britain's Got Talent viewer
However, people watching at home were less convinced by the trick and logged onto social media to discuss it.
"Oh come off it, they prepared a separate set of tickets backstage and slipped it into his hands. #BGT,” posted one person.
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A second wrote: "A stagehand placed the card with the right info on it inside the handle of the sword. Why have I ruined every magic act on #BGT this week."
Richard Jones performs a trick for the audience on Britain's Got Talent The funniest moments on The Chase Fri, January 13, 2017
The Chase: A round up of the funniest moments of TV quiz show.
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Richard spears the right card on his sword on Britain's Got Talent
A third added: "He actually said the number 333 when he was asking Alesha to pick a number. #bgt #magician."
This is not the first time Britain’s Got Talent viewers have tried to guess how an act has performed a magic trick, earlier this week it looked like Josephine Lee’s illusion may have been unravelled.
Tonight will see more acts going head-to-head in the fifth semi-final before the grand final on Saturday evening.
Britain's Got Talent airs on ITV tonight at 7.30pm.