I got naked with Madonna in college — this medical crisis is no match for Madge

Before Madonna was vogueing across the world, she was a 19-year-old dance student at the University of Michigan.

For the first time, her ballet classmate and fling Peter Kentes, now 72, is sharing his story about his relationship with the “flirty” global icon — which even included a naked shower together.

He is also revealing rarely-before-seen, intimate images and video of her from their college days — circa 1978 — as she currently battles a shocking health crisis that delayed her much-anticipated world tour.

The photos are a far cry from the superstar image she built over her four-decade career, with her latest feat — a self-congratulatory tour nodding to her body of work, aptly called “Celebration” — disrupted by a bacterial infection and hospitalization last month.

In pictures obtained by The Post, the pre-fame Madonna poses for Kentes’ camera in a red and yellow floral print dress with white crew socks and pink ballet flats.

Kentes, who still teaches dance at the university, was a 28-year-old graduate student at the time and had cast Madonna in his thesis performance.

Kentes told The Post on Tuesday that he took pictures of each dancer included in his piece outside against a brick wall.

In one of the images, Madonna playfully bends over, exposing her blue underwear to the sky.

“She was very willing to be photographed,” Kentes told The Post. “She was very open and very trusting. I thought the results were great and have always thought those shots were really exceptional.

“Madonna danced in front of the audience as those photographs were projected on the wall behind her during the performance,” he added.

While Kentes and Madonna were friends, he also found the soon-to-be-rising star’s “energy” and “very outspoken” ways to be quite attractive.

“She was a workaholic with intense physical energy,” he recalled.

“Instead of just sitting around, she’d be doing things like pushups, working on her body, stretching and so forth,” he claimed. “She seemed more like she was there for the dancing and less for the academics, although she was a very good student.”

Kentes added that Madge was very flirtatious with “most everyone” — but said the two connected on another level.

“I think the fact that we’re both sort of different — and she was a little different — made us sort of attracted to each other,” he explained.

“Her sort of brashness, you know, I just found that quite endlessly entertaining, and it didn’t really put me off like it did with some of the other older dancers.”

The Post has contacted representatives for Madonna for comment.

Kentes also claimed that he and the future “Express Yourself” superstar shared a few romantic moments.

“We were not lovers — we did take a shower together,” he confessed. “And we did kiss.”

He admitted that he “would’ve taken it further,” and while a long-term relationship was “appealing,” Kentes knew it wouldn’t last.

“I thought, ‘Her ego is always going to be first and what I do will be second,’ and that’s not what I wanted,” stated Kentes, who also went dancing at nightclubs with her and other dance students.

Still, the duo had lots of fun together, as exhibited in one of Kentes’ anecdotes.

“We performed together as a touring company doing liturgical dances,” he told The Post.

“We were rehearsing for a performance in this large church. And she said, ‘Peter, what’s your address?’ So I told her but wondered why she’d want that.

“A week later, I started getting calls from the church because she had filled out one of those guest forms in my name. So I was getting calls about joining the church.

“It was funny stuff like that, you know?” Kentes laughed. “She’s a jokester and trickster. She’s very entertaining and fun to be around.”

Kentes said he hasn’t spoken to Madonna since driving her to the airport in 1979 when she booked a one-way ticket to New York City to try and make it in showbiz.

However, he and Madonna both kept in contact with their former ballet teacher, Christopher Flynn.

Before Flynn died in 1990, he apparently told Kentes about the Material Girl: “She hasn’t changed a bit. She’s still our Madonna.”

“I took his word on it,” Kentes told The Post.

Madonna recently postponed the United States leg of her highly anticipated “Celebration” tour as she continues to recover from her recent unexpected health crisis.

The “Express Yourself” singer told European fans she’d be back onstage come October, and she is currently still scheduled to bring the show to Brooklyn’s Barclays Center on Dec. 13 and 14.

Despite the extensive disruption, Kentes has faith that his former flame will keep her promises.

“She’ll conquer the health issue and make sure she puts on the tour,” he said. “She’s the kind of person that is most herself when she’s performing on stage, so she’s got to get back on stage.

“I think she’ll do everything she can to do it. She’ll make a comeback.”

And when the US tour dates are rescheduled, Kentes said he plans on attending a show.