Art investors with a passion for rare Warhols must be beside themselves...

Just a day after the artist's Sixteen Jackies met its $20m estimate at Sotheby's New York, across Queensboro Bridge at Christie's two highly prized self-portraits go under the hammer tonight.

Self Portrait (1963-64), Warhol's first self-portrait, has a $20-$30m price-tag and a legion of admirers.

Christie's Brett Gorvy comments: "Self-Portrait heralds the beginning of Andy Warhol's superstardom. With dark sunglasses an oblivious gaze, Warhol was ahead of his time in creating a new archetype of glamour."

Warhol's last self-portrait, produced in 1986, just months before his death, will vie for top spot at the sale with a $30-$40m estimate.

Warhol first self-portrait has a $30m high end estimate

The auction house's Amy Cappellazzo states the nine-square foot work "speaks powerfully of human existence and the dark, ever-present simplicity of death".

It was produced for an exhibition of new Warhol self-portraits at London's Anthony d'Offay Gallery in 1986 and is the only one of seven self-portraits he produced in 1986 to remain in private ownership.

A 1986 purple version of the work was sold last year by Sotheby's for $32.5m to a private museum, a record for a self-portrait by the artist.