This is "A Woman Drinking with Two Men" by Pieter de Hooch. Painted in the Dutch tradition, it's a scene that leaves us wondering what's really going on.
One of the figures has her back to us, so we can't see the expression on her face. But since the man behind the table seems to be using two clay pipes as a pretend violin and bow, and his companion gestures as though conducting a duet, she may be singing.
Scenes like this were characteristic of seventeenth-century Dutch painting - they're open to interpretation. We can't be sure if this is an innocent musical gathering or something more salacious.
But what really draws you in is the sense of being in a real space. De Hooch used black and white floor tiles to create this illusion, helping our eye understand where everything fits together.
And if we look closely, we can see that de Hooch didn't just paint what he saw - he adjusted it for effect. The woman in the foreground is slightly too tall relative to the other figures... but you probably won't notice that at first glance.
A Woman Drinking with Two Men 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.