Michael J. Fox got a tattoo on his forearm for a meaningful reason: Here's the 'long story' behind his ink

You can't, unfortunately, travel back in time to undo bad tattoos -- so before getting inked, MIchael J. Fox put years of thought into his.

Back in January, Fox, 57, posted an Instagram of his brand-new forearm tattoo, captioning it, "First tattoo, sea turtle, long story."

The actor explained the significance of his new body art to Fortune during its Brainstorm Health conference in San Diego this week.

"It was New Year's 1999, and I went swimming and I saw a turtle, kind of a damaged little turtle," Fox recalled. "And I followed him around for awhile. And I came out, and I decided to start the foundation."

The turtle is shown swimming through five hoops, representing Fox's five decades of life, as well as "the idea of emerging and coming into something new all the time," he said.

The photo is just one of a few dozen personal snaps Fox has shared on Instagram. In March, he posted a sweet, sunny photo with wife Tracy Pollan, who he wed more than 30 years ago.

The couple wed just a few years before Fox would be diagnosed with Parkinson's, a battle he would keep private until the late '90s.

During his Fortune sit-down, Fox said he's been surprised by a few things during his decades with the disease, not the least of which being: "I'm still standing."