"You try and put sunscreen on a kid, it's literally like herding cats," said Jackman, known for his role as Wolverine in the "X-Men" franchise.
The youngest of five children, Jackman said he spent his childhood outdoors, trying to keep up with his brothers under the blazing sun. He said he was not told to apply sunscreen.
"It was all outdoors," he told ABC News. "I don't think my dad or mom ever bought it or made us put it on. ... The thing I remember most, the rule about being outdoors was you weren't allowed to swim within half an hour of eating. ...And it's not true."
What is true, according to the publication JAMA Dermatology, is that one in five Americans will develop skin cancer at some point in their lives.
Jackman said it was while filming "X-Men," that he noticed a speck of blood on his nose.
"I thought somewhere in the fight, I hit myself, right, which is not unusual," he said. "I casually mentioned this to my wife who's like, 'Get it checked. You've gotta get it checked.'"
"He actually, in real time, in my office, was sending Instagrams," dermatologist Dr. Michael Albom said. "That's very unique."
These days, Jackman said, his children are the ones looking out for him.
"You know, it worries them," he said. "They're always saying to me, 'You know, Dad, sit in the shade.'"