Former WESTLIFE singer BRIAN McFADDEN has slammed the boyband's collaboration with MARIAH CAREY as 'a shambles'.

McFadden, who left the Irish group earlier this year (04) to pursue a solo career, believes musicians should only ever team up to record a track together if the moment is right.

And the 24-year-old star still cringes at the memory of Westlife and Carey's cover of PHIL COLLINS' AGAINST ALL ODDS.

He says, 'I don't think collaborations should ever be pre-planned. When Westlife did it with Mariah Carey it ended up being a shambles.

'The best collaborations are when you just realise it should be one and it just happens.'