(click image to enlarge)
Label on the orignal backboard read "I bequeath this dear portrait of Signor to the artist and donor Mrs Alfred Southerby. Lennox Lodge, 54 Lennox Gardens".
The drawing is of Watts in the drawing room at Limmerlease, his house at Compton, Surrey. it is based on a photograph taken in November 1903 and reproduced in M S Watts, George Frederick Watts: the annals of an artist's life, 1912.