By Piya Sinha-Roy INDIO, California (Reuters) - Hip hop duo Outkast reunited for the first time in eight years a the Coachella Valley Music and Arts Festival on Friday, and brought a taste of old school hip hop with them to the stage. Outkast, formed by Atlanta rappers Andre 3000 and Big Boi, kicked off the anticipated set with "B.O.B" from the duo's 2000 album "Stankonia," before taking it back to the 1990s with singles such as "ATLiens" and "Skew It on the Bar-B." "It's good to be back," Big Boi, real name Antwan Andre Patton, said on the Coachella stage against the backdrop of the Southern California desert lit up at night.