Jessica Simpson Busts Out: Photo

By Alison Schwartz

06/23/2012 at 02:00 PM EDT

Lately, Jessica Simpson has been working up a sweat (and rocking some serious workout gear) as part of her post-pregnancy weight-loss plan.

Not that she seems to be anything but comfortable in her skin – hot momma alert!

"Just taking a walk around the block," she Tweeted Friday, alongside a rather revealing snapshot – is that a pedometer in her cleavage? "Street legal???"

Since welcoming daughter Maxwell Drew with fiancé Eric Johnson May 1, Simpson, 31, hasn't shied away from talking about her post-baby, um, assets.



"She latched on at the very beginning. Nursing is a full-on job," she previously told PEOPLE of breastfeeding. "Sometimes I worry she's not getting enough, but it's been an amazing experience."

Simpson added: "It's the worst if I have to pump and give Eric a bottle to give her. I miss holding her and having that closeness."

For now, her fitness motivation doesn't have much to do with the scale – or showing off those curves at the beach.

"It would be nice to feel comfortable in a bikini, but that's not my goal," Simpson, who is working with Weight Watchers to get back in shape, told PEOPLE. "I just want to fit into jeans!"