La Roux at Governors Ball

La Roux performs during the 2014 Governors Ball Music Festival at Randall's Island on June 6, 2014 in New York City. 

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Although La Roux has let five years pass since the breakout hit "Bulletproof" made them a pop commodity in the U.S., the group sounded like it had never left the scene when Elly Jackson and her backing musicians performed at the Gotham Tent on Friday afternoon at Governors Ball on Randall’s Island in New York.

Alternating new tracks like "Tropical Chancer" and "Uptight Downtown" with old staples "I'm Not Your Toy" and "In For the Kill," Jackson said little to the crowd, but the evolution between the electronic tracks from 2009's "La Roux" and the fuller, disco-centric songs from the upcoming "Trouble in Paradise" spoke volumes. The new set is due July 8 on Cherrytree/Interscope.

After the performance, Jackson told Billboard that she didn't think the crowd loved the performance based on its energy -- but judging from the back of the Gotham Tent, "Bulletproof" and the other gems produced one big dance party.

Governors Ball 2014: Videos, Photos and More

Jackson also talked about how voice issues and fatigue influenced "Trouble in Paradise.” After wrapping a tour in early 2011, she found herself unable to sing falsetto. After months of seeing throat specialists, she was diagnosed with residual muscle tension brought on by a form of performance anxiety. The problem was eventually solved with the aid of a confidence therapist.

La Roux Returns After 'Burnout' and Vocal Problems: 'I Wasn't As Hardcore As I Thought'

“It definitely changed me for the better,” she says. “I learned a lot about myself, how to do my job and how best to handle things. I still get worried sometimes, but I think it’s good to talk about it, because if other people have this problem at least they’ll know somebody else had it as well. To me, nobody else had ever had this problem and that was really horrible.”

Billboard's Governors Ball 2014 Video