Credit: FameFlynet Pictures

Bing Bellamy's bodacious mama!

Kate Hudson delivered son Bingham "Bing" Hawn Bellamy on July 10. And now, eight months later, the Something Borrowed actress, 33, is more than ready to show off her famous bikini bod, taut and slim as it was before her second pregnancy.

(Bing's older brother is Ryder, Hudson's 8-year-old with ex-husband Chris Robinson.)

In Cancun, Mexico March 16 with Bing's dad, fiance Matt Bellamy of the band Muse, Hudson showed off her physique in a tiny, black-and-white striped string bikini as she and her man lolled about in the sand and surf.

How did the Oscar-nominated actress (and daughter of Goldie Hawn) get back in such fighting shape? Dance, dance, dance!

According to a source, Hudson had a dance studio built in her L.A. home -- complete with state-of-the-art stereo system -- for daily, hour-long dance workouts. "It worked!" raves the insider of Hudson, who's also a fan of cycling. The Oscar nominee also kept to strict portions of protein and veggies, and stopped eating after 7 p.m. "She has no baby fat!" raves the friend.