A hi-tech bra which can boost a women's breasts by an entire cup size while she sleeps has been unveiled in the US.

The computerised bra works by creating a vacuum in small domes in the cups of the bra that gently stretch and pull the breast tissue. The breast cells respond by developing new breast tissue.

Powered by a tiny battery, the bra's makers Biometrics claim it has no negative side-effects and say that after 10 weeks of use a woman will find her breasts have grown by a whole cup size.

The garment costs around $2,500 and has been approved by the US Food and Drug Administration after initial clinical trials.