The baby will join big sister Viola Philomena, who turned two, earlier this month.
In an adorable picture on Twitter, Hilty, 35, indulged her sweet tooth while her 43-year-old husband sipped a wine. She wore an "eating for two" T-shirt and he matched it with his own "drinking for two" tee.
Fellow pregnant Broadway star Audra McDonald congratulated the couple, "Awww snap! Our play dates are gonna be lit! Right @LauraBenanti? Congrats Mama!!!!" Laura Benanti who is also expecting a daughter quickly replied, "#BestFriendsForever whether they like it or not! @AudraEqualityMc @meganhilty.