This portrait is placed here because, according to her article in thepeerage, she married in 1614 and then bore one child. She was his second of three wives. Her Wikipedia article is here.
From a Pinterest search; shadows filled in. Also posted to The Late Farthingale Era - 1590 to 1620 Album here.
Lady Jean wears a wide wheel farthingale with the hanging and false sleeves of the Spanish originals in this Gheeraerts portrait.
Keywords: Gheeraerts - Marcus the Younger, Jean Drummond, Jean Ker, Jean Kerr, Jane Ker, Countess of Roxburghe, Drummond family, Ker family, Countess, British, Lady-in-Waiting, Queen Anne of Denmark, frizzy headdress, jeweled headdress, earrings, partlet, high neckline, lace neckline ruff, fitted bodice, scoop décolletage, lace bertha, tabbed paned virago full false sleeves, lace back flared cuffs, hanging sleeves, bracelets, brooch jeweled bodice ornament, waist band, bows, wheel farthingale, midi-length over-skirt, maxi-length under-skirt, shoes, feather fan