Arthur performed a version of LMFAO's 'Sexy And I Know It' on the third live week of the show and won praise from all four judges.
However, the rendition has drawn comparisons by fans to YouTube singer Only1Noah, whose performance of the hit song was uploaded five months ago and has since received 13.5 million hits on the video-sharing site.
Angry users left comments underneath Only1Noah's video, including kay1951 who said "james arthur so not original how disappointing", with SilverMustang69 adding: 'Dear Noah… Please sue X Factor UK for using an "exact" copy of your interpretation/rendition of the song."
On Saturday, Louis Walsh called Arthur's song a "brilliant rendition", and Gary Barlow added that he thought it was "amazing amazing amazing" and "the performance of the series so far".
