Godiva

You may be looking for Guinevere Godiva.

According to the Eighth Doctor, Lady Godiva once rode a horse without a saddle, and in an immodest manner. The Doctor once offered her a stalk of celery to cover up. (AUDIO: The Eighth Piece)

Lady Godiva was among the notable women of Earth's history who were invited by Missy to join MADAM. (PROSE: Girl Power!)

Behind the scenes

The implication is that it was the Fifth Doctor who met her, as he always had celery on hand, on his lapel.