Little Xander's growing up fast!

Prior to making her first post-baby red carpet appearance Saturday in Los Angeles, Mad Men's January Jones toted her son, Xander, around town Friday on a mommy and me lunch date.

Stopping by Jamba Juice and Panda Express, Jones cradled her 5-month-old little boy, who donned a blue and white bib and white socks for the outing.

Welcoming Xander Dane Jones on September 13, the Mad Men actress, 34, has yet to disclose her baby's father, but pals say she's a natural mom. "She's in love with that boy," Mad Men's John Slattery has said of his costar, who was back to work mere weeks after giving birth.

"We're all so proud of her and happy for her and she's doing really well," costar Elizabeth Moss recently told Us Weekly.