She's the pen behind "Half of Me," the dramatic exploration of public versus personal personas on Rihanna's Unapologetic. She's also a co-songwriter on a group of tracks on Alicia Keys' latest, Girl on Fire, including the kiss-off/self-affirming single "Brand New Me."

And Simon Cowell has taken a shine to her, putting her on songwriting duty for several UK X Factor faces, including Leona Lewis and Cher Lloyd. Sand� spent years as a working songwriter before convincing the industry she could be an artist herself. Her debut, Our Version of Events, naturally features songs composed by Sand�, for Sand�. In spite her success, the challenge of writing songs continues to interest her � no matter where they turn up.

"When I look at songwriters who've inspired me, their songs work in any genre," Sand� told Radio.com. "That's why I always like testing myself like, 'Can I write a big pop thing?' And then go and write something that's completely different in a completely different genre with an artist like Susan Boyle. And then go write for Rihanna as well. I think that if you're good at writing then you have to be able to do it in any genre. And if the production changes, they song can still stand. I love that challenge."

Her style, very evident on the tracks recorded by Rihanna and Alicia Keys, seem to contain a confessional note that tracks with the public perception of the artists. But Sand� says the songs are entirely her own.