In the late 18th century there were three main Whig society hostesses, Georgiana, Lady Melbourne, and Mrs. Crewe. All were good friends and all were considered the ton and members of the Devonshire House set. All also qualify as tarts!
Frances Anne Greville was born in 1748 to two published authors, into a family with strong political connections, strong ties to the great minds of the time, and kickass girl power. Who could complain? Just sit back and absorb all of these connections. Fanny's mother, Frances Macartney, was besties with Lady Spencer so Fanny and Georgiana most likely knew each other since childhood. Fanny's Dad, Fulke Greville was besties with Dr Charles Burney, father of Fanny Burney so the two Fannys grew up together and were friends as well. Talk about friends in all the right places!
With this social upbringing it is no wonder Fanny grew up talking and talking and talking. All her life she was known as quite the chatterbox. Georgiana once complained that Fanny had lately been a bit of a sycophant with her and needed to stop cooing over her. Lady Douglas once stated that Fanny's "ideas came so quickly that [she] could not follow them" and assumed that neither could Fanny!
Fanny was also privileged enough to be considered a great beauty of the time. Which no doubt helped to attract her husband to her. She was married to John Crewe in 1766, joining two powerful Whig families together which worked out just perfectly for Mrs. Crewe who quite enjoyed playing hostess. Her beauty and wit also got Fanny in trouble as well. She succumbed to an affair with a frequent house guest and cohort of her husband's, Richard Sheridan. Fox was right when he said "she loved high play and dissipation."
Regardless of whether she was pretty or not or whether she was a big mouth or not, Mrs. Crewe's political influence cannot be denied. She like Georgiana and other society hostesses was the backbone of political causes. Organizing events to bring together the minds of political factions, participating in elections, and being prominent in public (and also risking reputation) in order to further the cause; Fanny did it all tirelessly. She died as Lady Crewe (due to her husband's elevation to Baron in 1806) in 1818.