LONDON (Reuters) - A portrait of British writer Charles Dickens that went missing for 150 years will go on display in London this week after being found in a market in South Africa.

The miniature watercolour and gouache portrait by Margaret Gillies was painted in 1843 as Dickens, in his early 30s, was writing A Christmas Carol.

The painting shows him clean shaven, with long, wavy hair, looking over his left shoulder, a contrast to the more common image of an ageing Dickens, with long bushy beard and messy, balding hair.

The portrait was last on public display in 1844 at the Royal Academy of Arts in London, only to disappear some time after, with Gillies writing in a letter in the 1860s that she was unsure of its whereabouts.

After a fruitless search, she reported it unaccounted for in 1886.

The 14cm-high oval portrait was found late last year in KwaZulu-Natal by an unknown buyer and has been restored.

London art dealers Philip Mould and Company now own the painting, which will go on display at the Charles Dickens Museum.

It is unknown how the portrait moved from London to South Africa.

One theory offered by the dealers is that it was taken to South Africa by family friends of the Dickens and Gillies family.

The Dickens Museum, situated at the author's former home, is trying to raise money to buy the portrait.