Pop singer Christina Aguilera and Motown legend Smokey Robinson will head the line-up for a Michael Jackson tribute concert in Britain in October, the organisers have announced.Several of Jackson\'s brothers will also perform at Cardiff\'s Millennium Stadium in Wales, as will his nephews who form the boyband 3T, despite opposition among some of the late singer\'s siblings to the concert going ahead at all. Fans have until August 16 to register for tickets to the October 8 show, which will cost from £55 ($90, 63 euros) for a restricted view and £87 for a standard seat, to a top price of £240 ($390, 274 euros).After several delays, the first artists in the line-up were confirmed as Smokey Robinson, Grammy award-winning singer Aguilera, singer-songwriter Cee Lo Green, British singer Leona Lewis and pop act JLS.British R&B star Craig David and rock band Alien Ant Farm have also signed up for the tribute concert.\"We\'re delighted that such exciting and globally recognised acts have joined the line-up to pay tribute to a music legend,\" said Chris Hunt, president of Global Live Events which is organising the concert.  \"This is going to be a spectacular event, and one not to be missed. I\'m also pleased to say that we\'ll be adding more amazing headliners in the days to come.\" US Director Paul Ring added: \"This concert will unite various generations and musical genres, reminding everyone of just how amazing a talent Michael was.\" The Millennium Stadium has a 74,500 capacity, but for fans who cannot attend the show will be broadcast to 30 countries in both 2D and 3D. It is the brainchild of Michael Jackson\'s mother, Katherine, his sister La Toya and brothers Tito, Marlon and Jackie.But two of his brothers, Jermaine and Randy Jackson, said the family should be concentrating on the upcoming manslaughter trial of Michael Jackson\'s doctor, which will begin on September 26 in Los Angeles.Conrad Murray, the last doctor to treat Jackson, is on trial for involuntary homicide in the King of Pop\'s death on June 25, 2009 at the age of 50 after an overdose of the anaesthesia propofol, which the singer used as a sleeping aid.