A new chaotic circuit is practically realized, for the first time, using a Lambert W-function. The circuit consists of three main parts. The first part employs a well-known Wilson current mirror, whereas the second part is a simple resistor at the two connected emitters of the current mirror. Both parts form a new circuit for a Lambert W-function by enabling a term of an emitter current to be simultaneously appeared on both sides of an exponential equation. Such a nonlinear equation is particularly well suited for realization of a Lambert W-function. The third part exploits a capacitor-inductor-capacitor (CLC) network and a resistor, which are connected to the nonlinear circuit of the Lambert W-function to allow for chaotic oscillations. The new circuit is capable of both a Lambert W-function and a current-tunable chaotic oscillator. © 2013 World Scientific Publishing Company.