Contestants on BBC One's The Voice are trying to fight off a virus which has left them struggling to rehearse.
Frances Wood, Joelle Moses and Jaz Ellington have been struck down by the vomit bug this week.
All three are on Will.i.am's team, but others on the show are said to be worried about becoming ill before Saturday's heat.
Teams coached by Will and Sir Tom Jones will be taking part during this weekend's edition which will see four acts leave the competition.
The BBC said it was hoping the contestants would be fit to take part in the programme.
A spokesman said: "We're making sure the sick artists are getting all the rest and recuperation they need, and barring any further outbreaks, are confident they'll all make it back for Saturday night's show."
Meanwhile, Will.i.am has defied BBC bosses by refusing to stop tweeting during the live shows.
The Black Eyed Peas star provoked some criticism when he was frequently spotted tapping away on his Blackberry during performances last week, but said on Twitter he plans to keep doing it.
Will tweeted: "I told the bbc: 'It may seem odd me tweeting... but trust me... this will be the norm one day & people are going to copy it'.
"I'm not going to stop tweeting during live shows... I think it allows people to live the moment with me as I'm in it."