This determined looking sitter is just 13 years old. The Old Rags posting for this portrait has this note, "Funny fact about this portrait: Louise Augusta was supposed to have been painted in one of the chemise a la reine dresses that had just come into fashion, but when Jens Juel was sketching her in the garment, one of her brothers ministers walks in and pleads to her brother that one could paint an actress or a mistress that way, but not a princess (especially not a sister that was rumored to be the illegitimate child of her ill-fated mother and her fathers physician). So poor Louise had to change into one of her ‘old-fashioned’ frocks (I think she looks lovely, even though she complained that it was ‘ancien’). After her marriage to the Duke of Augustenburg, she found out that the sketch had been finished into a painting and purchased by her father in law."
From www.altesses.eu/max.php?image=974c97e36e.