X Factor contestant Rylan Clark entered a war of words with Gary Barlow by blasting the show's chief judge in an online outburst.
He hit back after Barlow - who mentors former cruise ship entertainer Christopher Maloney - is reported to have been critical of Clark's abilities as he played a gig earlier this week.
Clark, who is known for his flamboyant routines on the ITV1 show, has faced repeated criticism from the Take That star for his vocal limitations.
The 24-year-old from Essex posted a message on Twitter which appeared to snipe at Maloney.
He said: "I'd rather be 'absolute s***' than just stand there and sing the same old stuff every week on the spot ....... £boreme GBarlowOfficial."
Clark, alluding to the fact he entered an entertainment show rather than a showcase for the clarity of his voice, added: "And I entered The X Factor.... NOT The Voice..... Cheers."
Both messages were later removed.
Barlow reportedly told the audience at a Mencap concert: "I'm serious.
"What are we going to do about Rylan?
"I might have to be honest on Saturday night and go, 'Rylan, I thought that was absolute s***e'."
Clark and Liverpudlian contestant Maloney have come under fire for remaining in the contest when judges' favourites such as 16-year-old Ella Henderson have exited the competition.
But Clark, who is gay, told Twitter followers some of the abuse he had received online had been "absolutely disgraceful".
"Some of you should be locked away for your comments regarding my sexuality," he added.
"I TOTALLY understand I haven't got the best voice in the competition but have proved that I can just stand there and sing...
"I look forward to the day when people see that I have been honest and genuine throughout and polite to everyone during this process."
His comments come despite contestants being briefed on how to use social media, with programme bosses apparently making an adviser available at all hours of the day.
They are advised not to engage in negative comments.