Mtv - N.E.R.D. Brings Girl Onboard For New Album

Rap trio N.E.R.D. has added a feminine touch to its line-up - unknown female singer RHEA.

The three hip-hop males, fronted by Pharrell Williams, have signed up the musician to appear on the band's next album Instant Gratification, and to perform in concert.

The classically-trained singer auditioned for the group over the internet, and Williams insists Rhea's talents have added a new aspect to their sound.

He tells MTV.com, "Musically, we're just somewhere else (with Rhea). The music is now very 3-D. It's something you have to hear. But you'll see.

"The music is very three-dimensional. We're just really excited. We feel like N.E.R.D. has always been the punks of hip-hop and the outcasts of alternative music - just a little different. But this time, we're taking no prisoners."