WATCH: Get a Sneak Peek of Sarah Silverman as Betty's Ex-Girlfriend on Masters of Sex

In season one of Showtime's hit Masters of Sex, many of you probably remember Annaleigh Ashford's sassy, loveable prositute Betty DiMello talking about her girlfriend, Helen. Of course, times have changed for Betty; she's now married to a man (and a series regular!), and the two are just starting to open up about secrets of their past. And because there couldn't be a more inconvient time for things to get shaken up, this week we get to meet the famed ex-girlfriend Helen, played by none other than Sarah Silverman. Check out the teaser below and the new episode on Sunday: