R&B singer Ciara is flaunting her new toned post-baby body by stripping down to her underwear.

The Goodies hitmaker welcomed her first son, Future Zahir, in May (14), and just four months later, she is showing off the hard work she's put into diet and exercise since becoming a mum.

Ciara posted a photo of herself lying in bed with just a black bra, Calvin Klein underwear and a black sweater hanging from her arms on Instagram on Friday (03Oct14).

She added the caption, "I feel so proud to say that 4 months after delivering a 9 lbs. 10 oz. baby, I can finally rock My Calvin's!"

The singer posted another photo of herself posing in a grey sports bra and underwear, and wrote, "After Delivering My Son I Feel Like There’s Nothing I Can’t Do. I Feel Like I Can Conquer The World. A New Me. So Proud To Rock My Calvins 60lbs later!!"