Credit: Courtesy of Vanessa Lachey

Mama's back!!! Let's do this G! @selfdiscipline #HeartAndHustle #HealthyMommyIsHappyMommy

A photo posted by Vanessa Lachey (@vanessalachey) on Feb 18, 2015 at 1:37pm PST

Get it mama! Vanessa Lachey is hitting the gym hard just one month after welcoming her second child, daughter Brooklyn, on Jan. 5. Nick Lachey’s wife shared a photo of herself getting fit on Instagram on Wednesday, Feb. 18.

“Mama's back!!! Let's do this G! @selfdiscipline #HeartAndHustle #HealthyMommyIsHappyMommy,” she captioned a black-and-white photo of herself looking trim in a black tank and workout capris.

The second-time new mom doesn’t have much to work off, though. On Feb. 10, Lachey, 34, stepped out just five weeks after giving birth and looked almost exactly like her pre-pregnancy self while attending pal Molly Sim’s baby shower in Bel-Air, Calif.

And while she reveals she’s happy to be back in the grind of things, the entertainment correspondent couldn’t be happier to be mom to her baby girl and 2-year-old son Camden.

"I have been dreaming of this moment for as long as I can remember, the day I was going to meet my little girl,” Lachey shared following the birth of her daughter. “A friend recently told me how magical today was going to be because it's the day I would meet my best friend. I can't even begin to tell you how it felt to hold her in my arms for the very first time. Mommy, Daddy and big brother Cam love you so much already, Brooklyn! Thank you to everyone for your love and support, it means so much to our family. Xx, The Lacheys."