You may not know Emeli Sande by name, but if you’ve been listening to Rihanna or Alicia Keys lately, there’s a good chance you know her work.

Sande wrote the bonus track “Half of Me” on Rihanna’s 2012 album, “Unapologetic,” and co-wrote three songs on Keys’ latest, “Girl on Fire.”

In addition to those big-name collaborations, the 25-year-old Scottish singer has a best-selling debut album, “Our Version of Events,” in the United Kingdom. She brings her powerhouse vocals and piano-driven songwriting to the U.S. this week, kicking off her first stateside tour.

For years, Sande pursued music on the side. The singer studied neuroscience at the University of Glasgow for nearly five years, often commuting to London on weekends to perform.

“It got to a point where I was doing a show in London, overnight on the train and a lecture at 9 a.m. (in Glasgow). I was kind of going crazy,” Sande says by phone from London.

Her music career gathered enough steam that she decided to leave medicine for music full time.

“That was always an issue for me, always having a Plan B,” Sande says, quoting a lyric from her song “Where I Sleep.”

“I’d never just take the plunge. And it was a big lesson for me when I did leave medicine,” she says. “Because you really have no guarantee anything is going to work out, but if you love something, you have to make that sacrifice.”

Since then, the singer-songwriter has become a veritable hit machine for British pop artists, from Leona Lewis to Susan Boyle. She also has scored high-profile gigs such as the London Olympics, where she performed during the opening and closing ceremonies.

Sande’s songs carry a distinct edge. They fall somewhere between Rihanna’s in-your-face party fare and Keys’ neo-soul piano ballads. Her style is mature, both compositionally and lyrically, but without too much melodrama.

“The writers that I really look up to and admire are those that can really say so much and resonate with a lot of people without too many words and without being too self-indulgent,” Sande says. “So I try my best to kind of walk within those lines.”

Simplicity was a guiding principle in her songwriting process. The upbeat love song “Next to Me,” which is her biggest single in the U.K., was written with producers Hugo “Hoax” Chegwin and Harry Craze in a casual session outside the studio.

“For us, it’s just so funny hearing it on the radio so much because we wrote it by such simple means,” Sande says. “I just said, ‘I want to write a really simple song about someone being beside you.’ And I just love how we made it in one afternoon and didn’t think much of it, and just how people really connect to simplicity and an honest statement has been fantastic to watch.”

The raw, confessional quality permeating “Our Version of Events” is no doubt integral to Sande’s success writing for others as well as for herself. Even though she didn’t even meet Rihanna until after “Half of Me” had been recorded, Sande says she was able to capture the pop star’s discomfort with her own public image in a brutally honest way: “You saw me on the television / Setting fire to all the buildings / Yeah, I guess you saw me stealing / But you have no idea what I’ve been needin’. ”

“I heard that the song had really kind of meant a lot to her,” Sande says, “and had really come to her at a moment in her life when she needed to tell the world, ‘That’s just the half of me. Everything you’re seeing in the media, that’s not entirely all I am.’ ”

As Sande continues her ascent in the U.K. and internationally, she remains committed to authenticity. Adorning her right forearm is a tattoo of famed Mexican artist Frida Kahlo, whose courage to lay bare her own demons is what the singer says she strives for in her own work.

“The first time I saw her art, I just loved how brave it was, especially as a woman, to be so explicit, to be so unapologetic for all our flaws and kind of ugliness and at the same time make that beautiful,” Sande says. “I just thought, ‘What a gift.’ And what a gift to the world her art was.”