They are Mutya Buena, Keisha Buchanan and Siobhan Donaghy, and they're an English girl group who originated the Sugababes act in the late '90s. The Sugababes have reformed again and again as original members have dropped out over the years, starting with Siobhan and ending with Keisha in 2009. Oddly enough, the reason Siobhan left the group in 2001 was strife with Keisha.

The past 12 years seem to have been ones of forgiveness and growing up. The girls are now 28 and 29 years old, and set to release their first record together since 2000 later this year. Last week, they released their first single, "Flatline."

The Sugababes under these three girls was critically acclaimed, said to have been ahead of their time back in the late '90s and early '00s, and it seems things haven't changed much since then. In "Flatline," they don't sound quite like anyone else out there right now.

To me, the song is so interesting because it's different while still sounding like a mash-up of things that have come before it. It sounds one part Ellie Goulding, another part Haim, a smidge of Nelly Furtado, a dash of dance, a pinch of R&B, and so different from what they sounded like over a decade ago. And it's catchy, it's fun, it's summer.

MKS/The Sugababes in 2000