LONDON.- A rarely-seen portrait of the Duke of Wellington from a private collection and commissioned by one of his closest female friends is set to be a big draw at the National Portrait Gallery’s exhibition devoted to the Regency artist Sir Thomas Lawrence, which opens on Thursday 21 October. Apart from a two-month exhibition in Bristol in 1951, the portrait has never been seen in public.

The portrait – which shows Wellington in civilian clothes rather than military attire – is widely held to be one of the artist’s most celebrated paintings. It is also one of the most successful and revealing portraits by any artist for whom the Duke sat. It comes as close as any to penetrating Wellington's aura of heroism and capturing the essence of the man.

Commissioned in 1820 by Wellington's close friends the diplomat Charles Arbuthnot and his wife Harriet, whom he had met in Paris in 1814, the portrait was exhibited at the Royal Academy in 1822. Such was the intensity of Wellington’s relationship with Mrs Arbuthnot most contemporaries assumed they were lovers, while her husband Charles accepted their friendship. After his wife’s death, Charles moved in with Wellington and acted as his ‘Secretary’ for the rest of his life.

Among Lawrence's portraits of Wellington, this one is remarkable for the plainness of its conception and its intimacy. This seems to reflect the close relationship between Wellington and the Arbuthnots, and mirrors to an extent the private side of the hero which Harriet Arbuthnot reveals in her diaries. 'All other pictures of him depict him as a hero,' she says of the portrait which 'has all the softness and sweetness of countenance which characterises him when he is in the private society of his friends', and that 'the cloak is just like the Duke wears it, and the hand remarkably like!'

Exhibition Co-Curator Dr Lucy Peltz says: ‘While we will never know the true nature of Wellington’s feelings for Harriet Arbuthnot – and modern historians are sceptical – what is certain is that Wellington preferred the company of women and, if anything, the sensitivity and private register of this portrait could be understood as Lawrence’s response to the desires of both the sitter and the patrons.’

Wellington – who has been recently described as ‘vain about his lack of vanity’ – appears to have approved of this portrait above all others (and Lawrence painted eight between1814 and 1829), and it was engravings after this portrait that he most often gave to his friends and admirers as a memento. Writing in November 1820, Wellington declared that the portrait was ‘as good as any Lawrence ever painted', and later that 'Mr. Arbuthnot's picture is one of the best if not the best that he ever painted.'

Dressed in civilian clothes, punctuated only by the red ribbon of the Order of the Golden Fleece, the portrait was painted when Wellington was in transition from the theatre of war to the arena of politics.

The first exhibition in Britain since 1979 of the works of the great Regency painter Thomas Lawrence will open at the National Portrait Gallery in London on Thursday. Thomas Lawrence: Regency Power and Brilliance (21 October 2010 - 23 January 2011) will showcase the most important British portrait painter of his generation and explore his development as one of the most celebrated and influential artists in Europe at the start of the nineteenth century.

Among the most spectacular loans from the Royal Collection are the three monumental portraits (approx. 2700 x 1778mm) of Field Marshall Gebhardt von Blücher (1814), Charles, Archduke of Austria (1819) and Pope Pius VII (1820), which are normally displayed in the Waterloo Chamber of Windsor Castle. At the heart of the public tour of the Queen’s home, and part of the setting for ceremonial events, this group of some of the finest portraits by the artist who succeeded Sir Joshua Reynolds as Britain's greatest portrait painter, constitutes a rare and exceptional loan.

Thomas Lawrence: Regency Power and Brilliance includes Lawrence’s greatest paintings and drawings, many of which are rarely seen and which convey the power and originality of his work. Star exhibits include a recently rediscovered self-portrait, a drawing of Countess Therese Czernin and a painting of Emily, Lady Cahir, Later Countess of Glengall, which have never previously been seen in public. Of the 54 portraits in the exhibition, many have been generously loaned from private collections including Charles William Lambton, the famous “Red Boy,” as well as from public institutions such as the portrait of Elizabeth Farren from the Metropolitan Museum of Art, New York.

The exhibition, which has been organised by the National Portrait Gallery and the Yale Center for British Art, New Haven, will travel to the United States of America, where it will be the first substantial examination of the artist's works. Thomas Lawrence: Regency Power and Brilliance will introduce the artist’s paintings in all their beauty and virtuosity to a new generation of visitors and will re-examine his work in the light of recent scholarship on the art of the Regency period.