One of television's most iconic couples is set to split this fall. In an interview with VarietySimpsons executive producer Al Jean spoke about the 27th season premiere, which will include the Lena Dunham cameo we first heard about in January. In the episode the sudden discovery of Homer's long history of narcolepsy will cause a strain in his marriage with Marge severe enough for them to legally separate. During that separation he'll fall for his pharmacist, voiced by Dunham. 

Given our understanding of The Simpsons, we can expect Homer and Marge to be back together by the end of the episode. But there is still some mystery in the episode to look forward to. Jean said there will be cameos from other actresses in Girls. Ideally, Jemima Kirk (Jessa) will be included because her voice and accent are literally perfect. But as long as there's no Marnie, we'll be satisfied.