You can find out more about its surprising history in this Tate Shots video.
Posed away from the viewer, it's possible that this piece was always intended as a private piece for Sir George Bullough's eyes only or indeed for one or more of.
It seems unlikely the nude study was ever shown to the Marquess, and yet today it is on display in the National Trust property.
Artists sometimes use family members as their models, and here unusually depicts a tender moment with perhaps unexpected nudity — his proposal to his wife.
But here's a quick look at some of the other works in the UK that have a salacious or saucy history.
Certainly it wasn't four or five decades ago.