“#TBT #PrettyHappy #LOVE #AlmostFriday,” Hudson simply wrote as the caption to the shot.
The Almost Famous star recently published her guide to healthy living, Pretty Happy, which has become a New York Times bestseller.
"We’ve been programmed to feel like we’re under this great obligation as women to look and be a certain way," she told Self magazine earlier this year.
“And that’s not our fault. That’s what culture and society have gifted us as women. Thank you but no thank you.”