The 'This Is 40' actress, 27, showed off her svelte figure as she was photographed in LA with her first son Noah, 18 months, reported Us magazine.
Fox wore tight-fitting skinny jeans, a grey t-shirt, and a black tank top underneath.
The 'Transformers' star and husband Brian Austin Green, 40, welcomed their second baby boy on February 12.
During her pregnancy, the gorgeous brunette was hard at work filming the upcoming 'Teenage Mutant Ninja Turtles' film in New York City.