When Sia adopted two 18-year-old boys last year, she probably didn't expect to become a grandmother so soon.

Nevertheless, the younger of her sons - who are now both 19 - is the proud new father of twins, as she revealed in a new interview with Zane Lowe.

"I’m a fucking grandma!," she said, adding that her grandchildren have designated her 'Nana', although she said "I’m trying to get them to call me ‘Lovey'."

Sia, who is 44, announced in May that she had adopted the two boys last year as they were 'ageing out of the foster care system' and said that both had been through trauma recovery programs after spending so long in care. However, she said that they are both doing well and that “One recently came out, and he’s just blossoming and is the light of my life.”

She added that the recent incidences of police brutality against black people had made her 'very scared' for her kids, who are both black.  “I’m embarrassed that it took me to adopt two black sons to really understand what they go through on a daily basis,” she said. "When this reality is happening, and it’s what we should be addressing more than anything else… We can actually act, and we can actually try and get justice for Breonna Taylor, and Elijah McClain, just that there’s actually, we can have an effect. We don’t have to just feel sad and guilt.”

The Australian star recently had to deny accusations of racism when she mixed up Cardi B and Nicki Minaj in a tweet.