Kings of Leon  live at Lollapalooza 2014

Caleb Followill of Kings of Leon performs at Samsung Galaxy stage during 2014 Lollapalooza Day Three at Grant Park on August 3, 2014 in Chicago, Illinois.

Getty

"In Chicago we were just trying to get all the ladies dancing," Caleb Followill says of covering "Dancing On My Own."

Kings of Leon hasn't been riding its Mechanical Bull for a full year yet, but the group is ready to saddle up for a new project soon -- and, in fact, already has.

"We're always working on music," frontman Caleb Followill told Billboard during a conference call last week promoting the quartet's summer North American tour. "The other day we had a rehearsal and we ended up going in there and just writing music and we didn't rehearse at all. But that's kind of how we do it -- if you put us in a room together with our instruments it's hard for us to dwell on the past and play something we've played a million times. We would much rather create, so I think that what we have so far is really fun stuff. But, y'know, it depends on what time of year we make the album; if we make it in the winter time, we'll definitely probably have some sad songs on there, too."

Lollapalooza Highlights: Kings of Leon, Skrillex & More

Mechanical Bull, Kings of Leon's first new album in four years following a short band hiatus, debuted at No. 2 on the Billboard 200 last September and has launched the Top 20 Alternative Songs hits "Supersoaker," "Wait For Me" and "Temple." Drummer Nathan Followill noted that the new songs are "being received well. We're super excited to play the new songs every night, and it's fun to watch the crowd reaction and see which ones they know all the words to and the ones they don't know anything about." Caleb Followill, meanwhile, considers the set "definitely a grower... I think people, now that they've had time to digest what we've done, they're starting to realize the songs they like and also how much work we put into it."

Fans are still buzzing about how much work Kings of Leon put into their recent set at Lollapalooza. Not only did the group play three songs -- "Comeback Story," "Milk" and "Knocked Up" -- with an orchestra, but it also surprised the crowd with an encore cover of Robyn's "Dancing On My Own," a much lighter moment amidst the group's more serious-minded repertoire.

"I don't think it was something so people would take us less serious," Nathan says. "It was just an opportunity for us to show just a funner side of us and the fact we can step outside of the box for a second and do something that isn't normally as regimented as our sets are. We had played that song once before for a radio station in the U.K. and it was well-received via social media, and when it came time to do something special for Lollapalooza, it was a no-brainer to break that one out on such a great stage. The feedback has been great, so I'm glad we did it."

Caleb added that he became familiar with "Dancing On My Own" via parties his wife hosts. "Any time we go to these parties there's usually a DJ, and in order to get all those pretty women dancing you always play that song," he explained. "So I've always been fond of that song and Matthew's always been fond of that song, and we were backstage one day and I was actually playing the chords to 'Use Somebody,' or he was playing the chords to 'Use Somebody' and we realized that you barely had to change those chords and you could sing that song over it. So, yeah, whenever we did, when we had the option of doing a cover, we tried that one and it worked. So really in Chicago we were just trying to get all the ladies dancing."

Kings of Leon will be on the road in North America through October 5, followed by a performance at the Corona Capital Festival on October 12 in Mexico City.