Britain's Got Talent bosses have denied claims that Issy Simpson's magic trick was copied from another act.
Another contestant who auditioned for this year's show has claimed that the 8-year-old's routine was a "carbon copy" of his.
Carl Leek is said to have called in lawyers after performing for the judges this year with a similar trick as Issy.
On Saturday's show, Issy was seen asking Simon Cowell to pick a random card before revealing his choice was printed on her T-shirt.
Speaking to The Sun newspaper, Carl accused: “It’s ludicrous. The routine is literally a carbon copy. My act was built around the T-shirt and I have emails from the producers sending me images of Simon I could legally use as my first printed T-shirt was refused."
Carl claims he performed for the judges during the auditions earlier this year a week before Issy with his trick.
“During my audition I received four yeses, got a standing ovation from the audience," Carl says. “I just don’t understand how this has happened.”
He added: “The little girl will be innocent in all this — it is Simon and the show’s platform I am upset with and the constant ripping off of the nation and viewers."
However a spokesperson for BGT strongly denied the accusations.
They said in a statement: "Issy Simpson came to Britain’s Got Talent with her own routine and magic performance prepared, which she then duly performed at her audition.
“Any suggestion otherwise would be completely false.”
It's the second time this year that a BGT audition has been accused of plagiarism.
Last week Adam Keeler was hit with claims that his comedy routine was a rip off of comedy duo Raymond and Timpkins' act.
They took aim at Adam and the show, claiming they had turned down the chance to appear in front of the judges themselves.
"Oh dear. Shame on you BGT and Adam Keeler – how clever of you all to put an act on that blatantly copies our set," they said.
However Adam hit back and insisted he had never seen Raymond and Timpkins' act: “I have never seen the Raymond and Mr Timpkins Revue act so I can honestly say I’ve not copied it.
"Only 40 seconds of my audition was shown and I had other props that weren’t letters or signs.
“My normal act is 30 minutes long so unless people have seen both complete acts I would not know if they are similar.”
Britain's Got Talent continues Saturday nights on ITV.