This is "Marriage A-la-Mode: 4, The Toilette" by William Hogarth. Painted in about 1743, it's part of a series of six paintings that critique the excesses and moral decay of the aristocracy during this time.
In this scene, we see the Countess, who has become an aristocrat after her husband's death, receiving visitors as she finishes getting dressed. She's completely focused on her lover Silvertongue, who offers her a ticket to a masquerade. The opera singer and his flautist entertain the guests while a manservant serves them chocolate.
On the wall behind the Countess is a painting after Correggio, depicting Io being seduced by Jupiter disguised as a cloud. This is just one of several references in this painting that hint at the moral decay of the aristocracy. The little page boy holding a statue of Actaeon also adds to the commentary on the consequences of infidelity.
Hogarth's use of symbolism and visual detail creates a rich and complex picture, inviting us to look closer and draw our own conclusions about the themes and messages he's conveying.
Marriage A-la-Mode: 4, The Toilette hangs in The National Gallery on Trafalgar Square, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.