Jersey Shore's Ronnie Ortiz-Magro debuted rock hard abs after dieting and working out for just one month Credit: Courtesy of Ronnie Ortiz-Magro

Gym, tan, and more gym! Ronnie Ortiz-Magro whipped himself back into shape in just one month—and the result is very impressive! The Jersey Shore alum showed off his new rock hard abs via Instagram on Wednesday, May 28, noting that he'd been dieting and exercising for the past four weeks.

"I really let myself go after I got sick last year. It's been a long road. I am nowhere I want to be shape wise, but I feel better than I ever did," the 28-year-old wrote. (In April 2013, the reality star was hospitalized with kidney stones.)

Using hashtags, Ortiz-Magro also teased about how all the drinking during the MTV series is what did him in, and that the last time he had a six-pack was when he passed out on the beach—with a Corona on his chest. He is thankful, too, that he now can, um, wipe his own bum again. See pics of the Jersey Shore cast -- the way they were.

The Bronx native's new fit body is striking, to say the least. In the second selfie, (where he's ripped!) he traded in his faded jeans for a tight pair of Hanes underwear to really show off his skinnier frame.

Tell Us: What do you think about Ronnie's transformation?