Sia on Adopting One Son — and Ending Up with Two! 'I Just Felt So Blessed to Have Them Both'
Sia is opening up about her journey to motherhood.
The pop star, 44, adopted two 18-year-olds out of the foster care system last year after trying for years to get pregnant via in vitro fertilization with her ex husband, filmmaker Erik Anders Lang, she told InStyle in an interview published Tuesday.
Sia, who said she wanted to be a mom her whole life, took several years for herself following the 2016 divorce. Then, "everything changed" when she was watching a documentary about foster care.
"I learned the story of a 16-year-old boy and instantly fell in love with him. Older children have a really hard time getting adopted, and when I saw him, I said to myself, 'That's my son,' " she said, keeping his identity private.
Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
Sia continued, "I knew I wanted to help him. By the time I found him, he was 18 and aging out of the foster care system. I told him that I wanted to adopt him, and since he was an adult, he left with me that day."
Though she only planned to adopt one son, the "Chandelier" singer ended up with two.
"The only thing he asked was if he could also bring his cousin Che, who had lived with him in a group home. I had two spare bedrooms, so I said, 'Sure!' " she said. "And even though I'd never met Che before, he also moved in with me that evening. Later I found out that they weren't really cousins, just friends. [laughs] But I didn't care at all."
"I just felt so blessed to have them both with me," Sia added. "And I've realized over the past year that Che was meant to be my son too."
RELATED VIDEO: Hoda Kotb on Whether She'll Adopt a Third Child: 'You Just Wait and See If It's Meant to Be'
She went on to explain that motherhood hasn't been easy, noting the challenges of the foster care system that both her boys grew up in.
"The entire system is so underfunded and understaffed that there are not enough people to really monitor how the kids are being taken care of," she said. "And now my sons very much want to be a part of that change, so I am trying to give them the resources to do that."
"Most of their lives they've been conditioned to lie and manipulate, so the past year has been all about teaching them how to become rigorously honest and live in the moment without using any substances," the mom of two explained.
"There has been a lot of heartache. There has been a lot of lost trust and then a lot of regained trust. But I do trust them both. And I'm proud because they've come a very long way."