Sia revealed that she adopted one of her sons after seeing him in a documentary.

The "Chandelier" hit-maker spoke about her adopted children in the October issue of Vogue Australia

"I am obsessed with reality television and documentaries, and I watched a documentary and saw my son," she revealed. "I was like: ‘What? Like, he doesn’t have anybody. Oh my God. I’m going to find him and I’m going to be his mummy,'" she recalled. "And so, that’s what I did."

In 2019, she ended up tracking him down and adopting both him and his friend. Both boys were eighteen at the time of their adoptions and were at risk of ageing out of the foster care system.

The singer also shared how they've been trying to be productive while in quarantine.

"They are both finding it [quarantine] pretty difficult, one more so than the other," she confessed. "But they're both doing things that are like really good for them right now; that are really helpful. They're really doing a lot of educational stuff that's good for them."

This past July, Sia became a grandmother at just 44 years old.

"My youngest son just had two babies," she previously announced. "I'm a f--king grandma! I know, right? I'm just immediately horrified... no, I'm cool." She also shared that her grandkids call her "nana" instead of grandma.