Several news websites reported about YOSHIKI's appearance on the red carpet at the Grammy Award 2010 that took place on January 31 (local time).
There he announced that X JAPAN accepted the request to play at Chicago's music festival 'Lollapalooza' that will take place from 6th to 8th August, 2010.
If X JAPAN play there, they will be the first japanese rock band that plays on the main stage.
During the event that is lasting three days, 225000 visitors will be expected.

However, we still have to wait for official confirmation from X JAPAN, as there's nothing announced on their website, yet, or anywhere else.

Sources: Natalie, Sanspo, Sponichi, and others