But the boys have found perhaps their most unlikely fan to date in the form of the Chinese ambassador in London.
Her excellency Madam Fu Ying expressed her admiration for the Irish siblings in a letter to a British newspaper this week.
"I am impressed by the twins, John and Edward, for their determination and spirit in the face of a lot of criticism," wrote the official, whose residence borders the property which houses the contestants.
She was writing about her feelings on Simon Cowell's reality show after it was reported she had complained about disturbances caused by fans outside the X Factor house.
In the note she explained it was a misunderstanding, though – it was "embassy colleagues living nearby who complained about the noise" - and that she is actually a fan of the show.
"It was fun finding myself caught up up in X Factor fever and reading about the "diplomatic row" involving my embassy," she began in the letter to the Sun.
"My daughter emailed me wondering if she could fly in and join the screaming fans!
"I have to admit that I also enjoy watching the X Factor when there is time and have my favourite contestants."
Although she wouldn't reveal her top contestants, Madame Fu Ying had kind words for several of the other singers.
She praised Stacey Solomon for being "more and more brave" each week and Jamie 'Afro' Archer's "sincere and energetic voice".