In his magisterial Thomas Gainsborough Yale 2019, Hugh Belsey describes Portrait of a lady in a green dress c.1743 (cat 975) as one of Gainsborough’s three earliest-known oil portraits, along with Gainsborough’s famous self-portrait c.1740 – 42 (cat 366; Private Collection United States, formerly with Philip Mould), and a small oval of a young girl in pink c.1743 (cat 974; Private Collection, London Art Market 2005).
(c) Matthew Holbrook
Belsey notes ‘the colour harmonies and the strong drawing [of the lady in pink], repeated in the larger portrait of an unidentified woman in a green dress… The second painting bears distinct similarities to the self-portrait of 1740 – 42’ (Belsey 2019 Vol 1 p.2).
(c) left Matthew Holbrook, right Philip Mould
The similarity between the lady in green and the self-portrait is very striking. It impressed everyone when they first saw the painting. The two portraits have a stylistic kinship that identifies them as works by the same painter. But my father believes they’re more closely related than that, and he wonders if they’re brother and sister. That is a very interesting idea. They do look very alike.
Gainsborough had two sisters, Sarah Mrs Philip Dupont (c.1718 – 1795) – mother of his assistant Gainsborough Dupont – painted here by Gainsborough c.1777 (cat 295; Art Institute of Chicago)
(c) Art Institute of Chicago
and Susannah Mrs Richard Gardiner (1726 – after c.1777), in a portrait painted by Gainsborough at about the same date as her sister’s (cat 384; Tate Britain).

Both looked just like their brother, though he has more of a mouth, seen in the 1787 self-portrait (Royal Academy of Arts).

Gainsborough is not one of those painters who makes all his sitters look the same. He could always get a good likeness. He was famous for it. So, if Gainsborough paints the lady in green with a broad forehead, long nose, high cheekbones, thin mouth and strong chin, we can trust that’s what she looked like. In the flesh you can also see that she has slate grey eyes, like Sarah and Susannah Gainsborough, and like Gainsborough himself.
Sarah would’ve been 25 in 1743, a plausible age for the lady in green. Susannah was 17 that year, too young for our sitter, though only a year older than Gainsborough at the date he painted the lady in green. Sarah has a similar flash of expression to the lady in green, a direct, challenging look and the hint of a smile about to break.
The two paintings are stylistically very different. They’re 34 years apart. Gainsborough’s style, and fashions in British portraiture have changed in that time. Sarah Dupont is painted life-size, on a 30 x 25 inch canvas. The lady in green, like all of Gainsborough’s earliest portraits is small-scale, and the canvas is only 14 x 11 inches. Small portraits at this date, by all artists, tend to be slightly doll-like, with proportionately larger eyes, but the features and the expression of the two portraits fit each so well that I am convinced.
In the self-portrait 1754 (Houghton Hall, Norfolk) Gainsborough is 27, around the likely age of the lady in green. The Houghton portrait is just under life-scale, so the features are more proportioned. They certainly look like brother and sister to me.
At present there is no provenance for the portrait, so we can’t make a direct link with Gainsborough or the Duponts. If the Lady in a green dress is a portrait of Gainsborough’s sister, it would explain something that we found curious about it. This portrait is such an ambitious composition – a three-quarter length rather than the usual half-length – and such a show piece, with the elaborate costume and painterly fireworks going on. We’ve always wondered who would have commissioned such a grand portrait from a relatively unknown teenage painter. Many of Gainsborough’s earliest portraits were painted for his family and friends. When he was just starting out, he might have been short of paying clients to commission such a spectacular painting; but his sister Sarah could easily have sat for a portrait that he could use as whistles and bells advertisement for his incredible talents.