Jessie J, Sir Tom Jones, and Danny O'Donoghue will link up to form a supergroup as they rattle through each other's songs for the finale of The Voice.

The quartet will perform a medley of songs during the two-hour show on Saturday night as the BBC One talent contest winds to a close.

The stars will perform a "mash-up" of some of their best known tracks which include It's Not Unusual, Where Is The Love, Price Tag and Falling To Pieces.

The finalists - Bo Bruce, Vince Kidd, Leanne Mitchell, Tyler James - will also team up with each of their mentors to wow the audience, in addition to performing songs on their own.

Heiress Bo is the 5-4 favourite according to latest odds from bookmaker William Hill with Tyler - a pal of the late Amy Winehouse - ranked next most likely to win.

The show has seen its audience halve from its height early in the series, reaching a new low for the semis last Saturday with just 4.5 million tuning in.

Even appearances by Cheryl Cole and Kylie Minogue were not enough to rescue the plummeting ratings last weekend.

TV bosses are agreed that there need to be some changes to the format to make it appeal to audiences throughout the duration of the series.

The final - which will see the audience choosing the winner - will also feature guest appearances by Maroon 5 and Ed Sheeran.