The teenagers perform a cover of Pink's Perfect, surprising the panel when it's revealed there are two of them on sage.
"We sing together, we live together, we do everything together, we're like a married couple," they explain before heading out to sing.
Indie (the blonde one!) adds: "Girl bands are usually put together but we've made it together, we want to bring back that Spice Girls vibe... and so we think Jessie will like us."
But will any of the panel share our love for the tuneful pair?
Only nine spots remain on the Voice UK teams, and the panel are pickier than ever when deciding whether or not to press their buzzer.