The 36-year-old let loose with Dax Shepard on the actor's newest podcast episode and admitted to "going wild" all those years ago.
Putting everything on the table from drug use to alcohol, Harry didn't hold back with Dax, who has struggled with his own sobriety over almost two decades.
Their conversation started by Harry asking the star about teen substance abuse in America.
The Duke of Sussex then began questioning Dax's "awareness" about what caused his own struggles with addiction.
"For you, it was your upbringing and everything that happened to you - the trauma, pain, and suffering," Harry told Dax before bringing up his own past.
"All of a sudden you find yourself doing a s---load of drugs and partying hard," he continued. "Look how many other people do that as well. They wouldn’t have the awareness at the time."
Turning the tables on his own wild ways, Harry said on the Thursday episode of Armchair Expert.
"I certainly wouldn’t have had the awareness when I was going wild."
"It’s like why am I actually doing this? In the moment its like, this is fun. I’m in my 20s - it’s what you’re supposed to do," he added.
Harry's past has been riddled with accusations of cannabis use and alcohol drinking.
Speaking of those leaked party pics, Dax didn't hesitate to ask the royal about them.
"I'm really excited to meet you because, in full disclosure I'm the most ill-informed person on the royal family, at least in my circle," Dax told Harry. "You're the only one I ever knew and simply because you were in those awesome nude photos in Vegas. And I literally said to myself, 'This guy's a party!'"
"On top of that, I was like, 'God! This motherf--ker's got a good body!' You are in tremendous shape," he added, to which Harry playfully chimed in by stating, "Okay, now it's getting weird."
Harry also credited his hot body back then to his military service.
"That was a few weeks before I went to Afghanistan," he told Dax.
Harry's wild ways in his 20s wasn't the only topic he discussed.