'Superstar' hopeful Nathan James has upset production crew with his "unprofessional" behaviour.
The budding star - one of the last five singers in the ITV1 reality show - reportedly left a junior team member in tears by shouting at her after there were no spare seats for his guests to sit in.
A source told The Sun newspaper: "He must think he already is Jesus to be getting away with this sort of stuff.
"He is acting how a small man thinks a big star acts, but really he is making a proper show of himself - no big celebrities act like that. It's unprofessional."
Long haired Nathan - who previously auditioned for 'The Voice', but was left angry when none of the show's mentors picked him - also reportedly warned the show's workers "never touch the hair" while he was preparing for the show.
The source who saw the singer's outburst explained how it was sparked when he tried to bring extra guests to see him perform during filming of the programme
The onlooker added: "He had exceeded his ticket allocation and brought extra guests.
"It wasn't the first time he pulled that stunt but this time seats couldn't be found so he humiliated a member of staff and reduced her to tears.
"It was unsightly to watch and everyone is horrified."
'Superstar' is judged by Lord Andrew Lloyd Webber alongside Mel C, Dawn French and Jason Donovan, who are searching for a new actor to take the lead role in a production of 'Jesus Christ Superstar'.