John Jennings Esq., his Brother and Sister-in-Law Alexander Roslin (1718-1793)

The picture has something of this: people, wear, group, woman, two, portrait, facial expression, outfit, man, three, opera, theater, music, performance, costume, musician, singer, theatre.
Perhaps it’s a painting of a man and a woman sitting next to each other with a book in their hand and a man in a red suit and white.