Jessica Simpson showed off her sexy post-baby body and cleavage while going to dinner with fiance Eric Johnson and daughter Maxwell, 16 months, in Calabasas, Calif. on Sept. 24. Credit: AKM-GSI

Mommy's night out! Jessica Simpson got all glammed up to go to dinner with her family on Tuesday, Sept. 24. The 33-year-old mother of two flaunted her sexy post-baby body while enjoying a night out nearly three months after son Ace's birth. The former Fashion Star mentor was spotted leaving Sagebrush Cantina in Calabas, Calif. with fiance Eric Johnson and 16-month-old daughter Maxwell.

Simpson looked looked gorgeous and slimmed down in an all black ensemble of a blazer, shirt and skinny pants. She showed off her curves and flaunted her cleavage in the low-cut top, and accessorized with dark shades and a black handbag.

Johnson, 34, dressed more casually in a plaid dress shirt, dark jeans and brown boots. He carried daughter Maxwell, who looked adorable in a pink Pale Cloud dress, while leaving the restaurant. Baby Ace appeared to have been left at home for the outing.

Simpson recently opened up to Us Weekly about how her daughter is adjusting to being a big sister. "She was the first to meet Ace. At first, she kind of pouted a little bit because she's a daddy's girl and Eric was holding Ace and couldn't pick her up," she shared. "Now she's holding the baby. It's so cute to see. She carries two baby dolls around and we change their diapers. So she's a mom too!"

The busy mom of two also told Us that she and Johnson try and enjoy date nights -- even if they have to get a little creative. "Sometimes they're in the backyard, but it's still a date! I nurse Ace every four and a half hours," Simpson explained. "It's a long day, but Eric and I wind down and have some dinner while the kids are asleep."