The incredibly shrinking Simpson! Jessica shows off her VERY svelte figure for Weight Watchers shoot... four months after giving birth to son Ace

In the past, she has famously struggled with shedding her post baby pounds.

But Jessica Simpson was showing off a a spectacularly slimline figure on Friday, just four months after giving birth to her second child Ace.

The star posted a Twitter snapshot of herself in a field sporting a white unbuttoned shirt and skinny jeans which accentuated an impressively trim waist.