Labour spin chiefs dubbed David Cameron and George Osborne the "Jedward" of British politics today, warning voters: "You won't be laughing if they win."
A picture of the Tory leader and shadow chancellor mocked up to look like Irish X Factor act John and Edward has been put on the party's website and could be used as a giant billboard poster.
The twins' performances have split political as well as public opinion, with Prime Minister Gordon Brown dubbing them "not very good" but Mr Cameron calling them addictive.
Despite being described as a tuneless novelty act, the boys have survived a series of public votes, with some pundits, although not the bookmakers, tipping them to snatch a shock win.
On its website, Labour said: "This week David Cameron announced that John and Edward are his favourites to win X Factor.
"It's hardly surprising. David Cameron and George Osborne are the Jedward of politics.
"Hilarious to watch. All spin and no substance. But you won't be laughing if they win."
Asked if they would use the image more widely, a spokesman said: "We're in discussion with our creatives and have many visuals, some or all of which will be used in print, online and other formats during our General Election campaign."
The Prime Minister has regularly proclaimed himself a big fan of X Factor and was quizzed about his verdict on the twins by young people in Manchester last week.
"I don't think they're very good," he said.
He delivered his snub days after Mr Cameron conceded that their appeal was more down to being "amusing" than talented singers or dancers but said he was among viewers "nailed to your chair, waiting for the terrible twins to appear".