Lena Dunham, who recently signed a first-look deal with Netflix, helms a new rom-com film, Good Sex. After spending a decade in a failed relationship, pragmatic couples’ therapist Ally (Natalie Portman) is turning 40 and reluctantly dipping her toe back into the New York dating scene. But she gets more than she bargained for when she meets two men — one in his 20s and one in his 50s — who show her there is no set formula for good sex.

Good Sex just got a little sexier: Meg Ryan and Rashida Jones join Portman, Mark Ruffalo, and Tucker Pillsbury, who makes his screen debut.

Portman and Sophie Mas produce with their production company, MountainA, and Dunham (Tiny Furniture, Girls, and Too Much — which comes to Netflix...