Last month Demi Lovato: Dancing With the Devil made its debut on YouTube Originals. Elton was on the first episode of the four-part docuseries, and spoke about the difficulties of fame at a young age.
The series follows Demi's recovery following her near-fatal 2018 drug overdose.
Elton is also on the fourth and final installment, which is now streaming on YouTube. He says that addiction is ''a lifelong thing,'' but it's possible to have a great life.
''I've been sober 30 years. I've had the most incredible things happen to me. And I'm hoping she does too, because she's such a great girl.''
But he's disappointed that Demi has decided moderation is the answer instead of completely avoiding alcohol and weed. At the same time, he admires Demi for opening up about her addictions, as well as the stress of fame at such a young age.
''You are put on a pedestal and you're not supposed to be human. But of course we're not perfect, we're all human beings. She's human and she's adorable and she's brave.''
Elton wrote on Instagram that Demi's courage will inspire countless others and that he is honoured to be in her documentary.
Their friendship began in 2016, when Elton invited the former Disney star to sing Don't Go Breaking My Heart onstage with him. A couple of years later, pop and rock artists reinterpreted some of Elton's songs on the album, Revamp. This included Demi, who did Don't Go Breaking My Heart again, this time with Q-Tip.