CHICAGO (AP) -- Get ready to dance, Lollapalooza fans.

This year's three-day, sold-out mega-festival that starts Friday on Chicago's lakefront will have well-known headliners like The Red Hot Chili Peppers and The Black Keys. But it also will have a special focus on dance music. Two electronic heavyweights, Avicii and Justice, will play main stage shows this year.

Festival founder and Jane's Addiction lead singer Perry Farrell says he looks at the lineup of more than 130 artists as a guide to what's happening in music.

The festival also is expanding the stage that has hosted dance and electronica acts. Last year's tent didn't allow enough room for the more than 15,000 fans who wanted in.

Ferrell started the festival in 1991. It is in Chicago for the eighth year, taking up more than 115 acres and eight stages.