As weddings go, it sounds like Allison Williams' one would have been fun to attend. (And, to think, we were just talking about her fictional wedding earlier!)
As her Girls character Marnie was getting married this season, Williams decided to get married in real life because she's a method actor (and you know because her husband proposed to her and they were in love and all that).
Williams asked Rita Wilson, who plays her mother on the HBO show, to sing at the wedding. Being the legend that she is, Wilson agreed and also put her husband, one Mr. Tom Hanks, forward for a job at the wedding.