Charli XCX co-wrote Icona Pop's "I Love It." (Jesse Jenkins) Charli XCX co-wrote Icona Pop’s “I Love It.” (Jesse Jenkins)

At 14, Charlotte Aitchison played her first show. Since then, the 21-year-old Brit — now going by the name Charli XCX — has conquered the charts as a songwriter, toured the world and released her major-label debut, “True Romance.” Yet darkness lurks in even her most anthemic, ’80s-inspired electropop songs, such as on the spooky but romantic album closer “Lock You Up.”

Lovin’ It

Charli’s biggest success so far has been Swedish duo Icona Pop’s inescapable, in-your-face anthem “I Love It,” which she co-wrote with producer Patrik Berger during a writing trip to Stockholm. “I knew from the start that I didn’t really want ‘I Love It’ for myself because it wasn’t part of the record I was making and I didn’t have a connection with it in my head,” Charli says of her more moody, chilled-out “True Romance” tracks. “I just knew I wanted to give it to someone.” Icona Pop sang over her original demo of the song, so Charli appears on the track and gets a featuring credit.

The Breakfast Club

When Charli was 14, an East London club promoter heard her songs on MySpace and invited her to perform at an illegal warehouse party. From there, raves, at which she would sing over her own prerecorded tracks, were a weekly part of the teenager’s life. “I became part of that scene for a while,” she says, “and then labels started to hear about what I was doing and they’d come down to these shows at 4 a.m., which was kind of weird. And they would try and meet me afterwards. I signed a deal and it went off from there, I suppose.”

The Next Stage

Touring as support for big-name acts has given Charli a chance to test her stage show on bigger crowds. “An artist like me isn’t supposed to play stadiums, so it was weird to do that, but it was great,” Charli says of touring North America with Coldplay in 2012. She also opened for Paramore in England recently. “I always get really scared when I play in the U.K., so that tour was kind of intense for me,” she says. But “I feel really lucky about how awesome the tour was and me not having a breakdown during the tour.”

U Street Music Hall, 1115 U St. NW; Sat., 6 p.m., $20; 202-588-1880. (U Street)