Mark Owen to face drink problem
Kylie Minogue, Mariah Carey, Leona Lewis also appear on REM cover
'We've already done bits and bobs,' he says
Plus David Walliams and Damien Rice to appear
Gary Barlow confirms their fifth member won't be coming back
Gary Barlow training spasm ahead of mountain peak attempt
Unknown plucked to support boy band stokes Wembley rivalry
Gary Go set for band's stadium shows
Singer's manager suggests a reunion could be on the cards
They will join Kings Of Leon, U2, Duffy and Girls Aloud at ceremony