Excited as Oliver Sim is that his band, British trio the xx, is making its New Orleans debut this Mardi Gras weekend, the moody, minimal, hushed music that the xx makes may be the ultimate counterprogramming to the raucous sounds of Carnival time in the Crescent City.

The same weekend that Mardi Gras parades roll and the French Quarter fills with revelers, xx members Sim, Romy Madley Croft and Jamie Smith will perform their ethereal songs at the House of Blues.

Still in their early 20s, Sim, Croft and Smith have already toured the world multiple times, released two albums and won the United Kingdom’s prestigious Barclaycard Mercury Prize for their self-titled album debut.

The xx’s New Orleans show is part of winter tour of the United States that includes sold-out shows in New York, Orlando, Austin, Texas, Tulsa and Tucson. Tours of Europe and Australia follow the trio’s American visit.

Having shows sell out weeks in advance in American cities astonishes Sim, one of the xx’s two singer-songwriters.

“It’s a surreal thing,” he said from London on the eve the band’s flight to the United States. “When we were making our first album, we didn’t really imagine it would leave London or the U.K., let alone take us to all these places that we’ve never been to.”

There was much interest in the xx in the United States from the beginning of the group’s recording career.

“On our first trip to America, we went to New York and played the CMJ Music Marathon,” he said. “We turned up to our show and there was a queue going ’round the corner. We were blown away. Yeah, we still have that feeling.”

Sim and Croft started the xx when they were 15, still in the British equivalent of high school.

“We were really starting to fall in love with music then,” Sim recalled. “We were going to lots of gigs and sharing new music. Then it was just kind of thought of, ‘Why not try it ourselves?’ But I still don’t call this my career. It’s just what I love to do.”

Early xx milestones included writing the band’s first original song and overcoming the group’s collective shyness to play its first gig.

“We were just playing little pubs in London, begging people to let us perform in their venues,” Sim recalled. “We didn’t have huge expectations. We were just having fun.”

An unintended career in music slowly became reality for the xx.

“For a very long time, there was no real intention to share our music with anyone else,” Sim said.

XL Recordings — the hugely successful independent British label that’s released recordings by Adele, Jack White and Vampire Weekend — began working with the xx when the band’s members were 17. The label gave the group use of a small in-house studio.

“It was just a space with a computer and a place where we could make noise,” Sim said. “We were given the freedom to do what we wanted in there. We didn’t have the pressure of constantly thinking about the studio time and how much money it cost.”

The xx’s debut album, released by XL Recordings, won the Mercury Prize in 2010. The award revived sales of the record, sending it to its highest U.K. chart position.

In recent years, Sim and his xx band mates have become much more confident on stage, but they’re still not the natural performers that friends and peers such as Mumford & Sons and Florence Welch (Florence + the Machine) are.

“Touring with Florence, I’d see that she’s so comfortable up there on stage every night,” Sim said. “That’s completely not us. Being on stage is something we have to work at. But I do love it now, and I love it more and more.”

John Wirt writes about music for The Advocate. He can be reached at jwirt@theadvocate.com.