THE tilt of his hat, the crossed arms, the way he glides effortlessly across the ice. This is not Sir Henry Raeburn's Reverend Robert Walker Skating on Duddingston Loch, but the work of an American artist painted just two years before the Scottish masterpiece.
Now it is claimed that The Skater, painted in 1782 by Rhode Island artist Gilbert Stuart, could be the inspiration for Raeburn's iconic work.
Dr Duncan Thomson, a former keeper of the National Portrait Gallery and a leading authority on Raeburn, says he believes it adds weight to his argument that the skating minister was the work of the Scottish artist.
In March, Stephen Lloyd, a senior curator at the National Portrait Gallery in Scotland, suggested that the Rev Walker was the work of French painter Henri-Pierre Danloux, while staying in Edinburgh. His theory was dismissed by two of the world's experts on Raeburn, Thomson and Professor David Mackie, who said there were several stylistic characteristics that typified it as a Raeburn.
In particular Mackie said the questions over the painting's uncharacteristic Raeburn style are down to the variable styles the artist adopted when he returned from a period in Rome.
Thomson said: "The painting of William Grant, from Congalton near Edinburgh, created quite a sensation when it was exhibited at the Royal Academy in London. There is no evidence that Raeburn saw it, but he may have done and it put the idea into his head. It makes it slightly less surprising that Raeburn would have painted a portrait of someone skating. Raeburn's more likely to have known about it than Danloux. This is before the French Revolution, so Danloux was still in France at the time.
"It adds to my argument, because Raeburn was far more likely to be aware of this than Danloux would have been."
Stuart's painting of the minister skating in Hyde Park hangs in the National Gallery of Art in Washington DC. It was painted during a period when Stuart was destitute in London and surviving on the generosity of Benjamin West, co-founder of the Royal Academy.
The inscription at the Gallery in Washington reads: "The painter recalled that when William Grant arrived to have his picture painted, the Scottish sitter remarked that, 'on account of the excessive coldness of the weather the day was better suited for skating than sitting for one's portrait'. Thus artist and sitter went off to skate on the Serpentine in Hyde Park. When he returned to West's studio with Grant, Stuart conceived the idea of portraying his subject on ice skates in a winter landscape, with the twin towers of Westminster Abbey far in the distance."
Iain Gale, art critic for Scotland on Sunday, said: "Raeburn would have known the work. When he came to look at the possibility of Robert Walker, he thought about the profile of Stuart's work. The similarities are obvious, but not sufficient to suggest that Raeburn was directly inspired by it."
The similarities between the paintings were spotted by American broadcaster Bob Cuddihy, who is hoping to persuade Sir Timothy Clifford, director general of the National Galleries of Scotland, to exhibit the two paintings side by side. Cuddihy said: "I first saw The Skater when I visited Washington in 1998 and thought wow! That is some resemblance."
The origins of the skating minister have always been unclear. From the time of Rev Walker's death in 1808, the portrait was passed down through his family, but it did not appear in any Raeburn catalogues.
It was bought for Scotland in 1949 at Christie's in London for 525. It had been sold 20 years earlier by one of Rev Walker's descendants.
In recent weeks, the National Galleries has amended its inscription next to the painting, pointing out the debate over its authenticity.