January Jones and her newborn son, Xander Dane Jones, dropped by a friend's house in LA today. The little guy was born on Sept. 13, and this is the first time the mother-son duo have been spotted out of the house together. Her Mad Men costars, meanwhile, are back to work filming the fifth season of their Emmy-winning primetime drama. The cast picked up their fourth consecutive win for best drama series this month, and even though January missed the afterparty celebrations, she was still a hot topic of conversation in the press room. Costar John Slattery passed along a message from January and Xander, saying, "Her baby had his fingers crossed, she told me that . . . We miss her tonight and we're super happy for her, all of us are. It's a great addition to our work family; we're very close here." January may be sharing cute stories about Xander with friends and family, but she's keeping some things top secret — like the identity of Xander's father, who wasn't listed on the birth certificate.