Singer Fergie has warned people experimenting with ecstasy that unless they quit taking the dance drug they will soon have a dependence on crystal meth. The BLACK EYES PEAS star-turned-solo artist was addicted to both crystal meth and ecstasy and suffered a dangerous drop in body weight as a result. The now clean Fergie says, "In my experience ecstasy leads to crystal meth. If it takes six months or five years, it will creep up on you - so don't be fooled."