The concerts are taking place at Ebrington Square on September 19 and 20.
No acts have yet been announced for the concerts, but they are expected to feature some of the biggest names in world music.
Ten thousand tickets went on sale for the concerts this morning.
Hundreds of people gathered overnight outside Cool Discs at Foyle Street and at Foyleside Shopping Centre to buy tickets when they went on sale this morning at 9am.
Thousands more went online at home and work in the hope of nabbing some of the sought-after tickets.
However, as expected, many people were left disappointed when the tickets sold out within a few minutes.