Interesting information found in Antonia Fraser's, "The Weaker Vessel"
The book states that by Royal Warrant, issued on August 21, 1660, Englishwomen were permitted upon the stage for the first time. Yet, it wasn't until 1670s the word ‘actress’ had secured in England the ostentatious connotation which would linger for another 250 years!
Yet, the first actresses often concealed their origins, while the honorific appellation “MRS” (pronounced Mistress) which they were granted – as opposed to the opprobrious “Miss”, which would make their material status hard to unravel.
By 1680s the word actress was virtually synonymous with that of “Miss” or “Kept Woman” – at least in the public’s eye. So, the burden of proof otherwise fell upon the individual actress. As a result, the convenient identification of actress and/or Miss led to young ladies becoming actresses precisely in order to secure a rich admirer!
Well then...Lilly would desire to be a MRS (Mistress) but due to her occupation...she'd would be considered a MISS.