Justin Biebersome advice on dealing with the transition from child stardom to adulthood.
The former teen idol, who was the 1970s equivalent of Biebs, has declared that he thinks the 19-year-old singer is rebelling in a bid to prove that he's a man.
Speaking to Closer Weekly, Donny said: "I'm just a normal guy, and Donny And Marie left me with such a wacky image.
"Since Puppy Love and Go Away Little Girl were such big records, I went through a period when I hated it.
"Justin Bieber is feeling the pains of this right now. Everyone thinks he's still the kid who sang Baby, but he's an adult, and he's rebelling to show people he's an adult."
However Donny also attempted to share the benefit of hindsight with Biebs - advising him not to fight it.
"You can't change history," he continued. "When you hit it so big at such a young age, time freezes in people's minds.
"You just have to live with the consequences until enough time goes by - 20 or 30 years, in my case. You get to a time when you end up embracing it."