Singer Sia is convinced she was "saved" after becoming a mother two adopted teens.

The Cheap Thrills star decided to expand her family last year, when the boys were both 18, just before they aged out of the foster-care system, and the musician is adamant the arrangement was just as beneficial for her as it was for them.

"It's a blessing for me," the 44 year old told U.S. breakfast show Good Morning America. "For me, I think they saved me, so I'm in heaven."

Sia, who often performs with a wig covering her face, has yet to share the identities of her sons, or details about their histories, but explains they both endured tough childhoods, and adjusting to a safe and comfortable lifestyle has taken them some getting used to.

"They both suffered a lot, and I've been able to get them the help - I have the resources to get them the help that they needed for their early trauma," she said.

"It's taken a year and we've had our ups and downs, but we've never been in a better place than today, in fact."