Photo of Lollapalooza 2015 by Shea Flynn

As Lollapalooza prepares to celebrate 25 years next summer, the Chicago fest is a fourth full day to its 2016 schedule.

Traditionally a three-day event, Lolla will feature over 170 acts next year from Thursday, July 28, through Sunday, July 31.

"There's a lot of really great music coming out in 2016," said Lollapalooza founder Perry Farrell in a statement. "With the abundance of talent that wanted to help us celebrate 25 years we got to thinking, 'How are we going to fit all those great artists in one weekend?' Then we thought about what a special day Thursday has become. When the party can't wait for the weekend, the movers and shakers make it happen on Thursday!"

Four-day tickets as well as one-day passes will be made available this spring, as will the festival lineup.