Kylie Minogue and Cheryl Cole set to take centre stage on The Voice

The duo are set to confirm they will perform during editions of the talent show as it reaches its climax.

The programme suffered an audience blow for its results show on Sunday - losing two million viewers in a week.

That came on the back of Saturday's edition of The Voice being beaten by Britain's Got Talent for a second consecutive week.

Kylie and Cheryl are understood to be brought in for slots in the later stages of the contest over the coming weeks.

Earlier it emerged singer Ruth Brown has narrowly edged ahead of rival Jaz Ellington to become a bookie's favourite to win The Voice.

The pair have established a clear lead ahead of the 14 other acts as the BBC talent contest begins its first round of public voting.

London singer Ms Brown, 20, has been targeted by racist internet trolls after she appeared on the show. A Metropolitan Police investigation is now underway.

Ladbrokes said that since the judges have finished whittling down their acts they have put Ms Brown, who is mentored by Sir Tom Jones, at 5/2 favourite closely followed by judge Will.i.am, who mentors, Jaz Ellington at 11/4.

David Julien and Becky Hill are far behind at 9/1 each.

The odds come as Ms Brown has revealed how she has been targeted by online bullying and racism. She said: Not only have I endured jibes of a racist nature but sick comments about my weight.

And she added they had even made jibes about her father, Lloyd, who died of stomach cancer, shortly before her audition last year.

Things have been said about my dad, too. At first, I was upset and cried my heart out. But I want to speak out because I hope it will encourage other people to fight back against bullies," she said.

In a defiant bid to shame some of those abusing her she even reposted some of the Tweets. One wrote: u ugly ******g black .....b****. Another Tweeted: u are a fat ugly ******. Your dad must think what monster did I give birth to haha.

The posts have since been removed ! from her Twitter account after she was asked to take them down by the BBC.

Sir Tom Joness duo Matt and Sueleen and Jessie Js act Cassius Henry are both tipped to be the first to leave the show with odds at 100/1 - after failing to attract a single bet since making it through to the final 20.

Will. i.am remains the punters favourite to coach the winner at 11/8, followed closely by Sir Tom at 2/1.

Jessica Bridge of Ladbrokes said: Its all about Ruth and Jaz. The other acts have a huge mountain to climb now if they want to win over the public vote.