Sia mentioned Christina in a California Chronicle interview session.

Aguilera contacted Furler’s management to arrange the collaboration, and so far they have written four songs together for the American singer’s next album.

“She was really good to work with. It was amazing,” Furler said.

“I think we both have similar strengths, but she writes a killer chorus and maybe I’m more of a verse person. Maybe I bring restraint.

“There’s a couple (of songs) I really love.”