Fergie's Abs Sizzle on Full Display in Black String Bikini

There's no doubt about it: Fergie has been workin' on her fitness.

The 42-year-old "Fergalicious" singer was spotted on a beach in Hawaii, baring her impressive abs in a black string bikini, aviator shades and adorable pigtails.

Fergie, who shares one child with husband Josh Duhamel, has been making headlines as of late for her bangin' bod, both on and off the beach. While she's always been physically active and fit, we can't help but admire her dedication.

Like most power couples, Fergie and Duhamel share a healthy morning routine to start their days off right: an energy-boosting breakfast the duo says they've been eating every day for the past seven years.

L.A.-based nutritionist Kimberly Snyder's Glowing Green Smoothie is popular among the Hollywood elite, and from Fergie and Duhamel's resounding praise, we can see why.

A post shared by @promistorytellersofficial on

"Kimberly introduced me to it on the set of the third Transformers movie. It’s spinach, kale, celery, apple, banana, pear—we’ve literally made it every day for the past seven years and it’s just like energy in a glass,” Duhamel said.

Even the couple's 4-year-old son Axl drinks the green smoothie, which they call "green goo."

“It used to take a little coaxing, but it’s become a great way to make sure he gets enough greens,” Duhamel says. Fergie, who also drank it through her pregnancy for a morning boost, has previously said the nutrient-rich blend is “like a buzz.”

The recipe involves a whole lot of fruits and vegetables, like spinach, lettuce, apples, pears and bananas; click here to get the full recipe. We'll be making it ASAP if it's going to help us see Fergie-style results next time we hit the beach — especially if it helps balance out that pizza we spotted in her hand above!

While news hit earlier this summer that Fergie is no longer a member of the Black Eyed Peas, we'll suffice it to say that as long as she keeps putting out sexy hits like "M.I.L.F.$", our Fergie addiction will be just fine.