The Andy Warhol self-portrait completed shortly before his death will go under the hammer on 11th May at Christies in New York and is expected to sell for up to $40m (£24.3m).

The red-on-black piece, measuring nearly 3m per side, is considered a landmark work by the American pop artist. Self-Portrait was painted in 1986, and is among the last to be exhibited before his death in 1987.

The other six large self-portraits Warhol painted in 1986 are all in museums or in collections.