January Jones pilates mad men flip flops los feliz

Her character on Mad Men was constantly struggling with her massive weight gain this season, but in real life, nothing could be further from the truth for January Jones!

The X-Men: First Class star showed off her slender post-baby 'bod in white pants and a low-cut tank as she headed to a pilates class in Los Feliz, on Tuesday afternoon.

Jones gave birth to son Xander last September, and while she's yet to reveal the identity of the baby daddy, we spotted the single star wearing a gold band on her wedding ring finger last week. Is it just a fun fashion accessory, or is Jan keeping another big secret?