A rare Andy Warhol self portrait in stark white and red, which had been in private hands for more than 30 years, will go on sale at Christie's in London next month.

The unusually large 1.8m by 1.8m canvas is one of 11 self-portraits in a 1967 series. Christie's estimates a price of £3 million to $5 million ($6m-$10m) for the painting.