Anthony Russell has 'barely sung a note' in rehearsals for The X Factor semi-final tonight.
One of the favourites in the series, Anthony is said to be battling illness ahead of this evening's show.
Anthony has been put on voice rest and is reportedly worried about securing his place in the final next weekend.
"While X Factor is gruelling on every singer's voice, Anthony's issues have been a real cause for concern in this crucial week," a source told The Sun newspaper. "He revealed to fans earlier this week he was on voice rest, but that didn't tell the whole story."
The insider explained: "He's either not been singing during vocal sessions or rehearsals or has missed them altogether.
"Anthony has a passionate fanbase, but knows he has to deliver a killer performance at the weekend as well.
"He's worried and has almost convinced himself he's going home."
Anthony is one of three acts left in Louis Tomlinson's boys category while all other judges are down to just one act each.
Celebrating the success of the trio this week, Louis told his followers on Twitter: "Still on such a high since the weekend. So proud of my lads for making it this far! Thank you to every single person who voted!! #xfactor"
Currently a total of 6 contestants are left in the competition.
Alongside Anthony in Louis' Boys category are Brendan Murray and Dalton Andre Harris. Ayda Williams leads The Overs with just Danny Tetley.
Scarlett Lee is the only act left in Simon Cowell's girls category while Robbie's last remaining group is duo Acacia and Aaliyah.
The X Factor airs on ITV this Saturday at 8PM and continues with the semi-final results show at 8PM on the Sunday. The theme is ABBA songs and there will be a guest performance from the cast of the Mamma Mia movie.