Sia is a "second mom" to Maddie Ziegler.
Sia
The 40-year-old singer befriended the 13-year-old dancer when she appeared in her 'Chandelier' music video and the teenager can't wait to be going out on the road with her pal on her 'Nostalgic for the Present' tour.
Maddie said: "I'm so honoured to be dancing with her for, like, six weeks. Sia's like my second mom. She's like a best friend to me."
Reclusive Sia is known for hiding her face under long wigs but the 'Dance Moms' star insists she is "beautiful" underneath all her fake hair.
Speaking on 'The Insider With Yahoo', Maddie said: "[Under the wig is] a beautiful, loving, caring face.
"People are always like, 'Is she pretty? Is she ugly?' I'm like, 'She's gorgeous!' And it's not just on the outside but on the inside, too."
Last year, Sia caused controversy with the video to her track 'Electric Heart', which featured Maddie, then 11, dancing provocatively with Shia LaBeouf - who is 17 years older than the young dancer - in a nude leotard.
Though she apologised for the clip, she insisted her words were meant just for one person.
She said: "I read one tweet from a woman who had found it triggering.
"She had been sexually abused as a child by an older gentleman. That made me feel sad but I don't really care about those other people.
"I essentially issued an apology to that one woman. I'm certainly not apologising for my work."
The video - which racked up over three million views in less than 24 hours on its release - caused some social media users to slam musician for creating the "disgusting" piece, with one user saying it "Smacks of child molestation #pervert #unacceptable #childabuse...Explain please!" while another fan simply wrote, "Sia's 'Elastic Heart' video is disgusting."
Sia said on its release that she felt Shia and Maddie were the right choices to depict "two warring" sides of her own personality.
Taking to her official Twitter account, she wrote: "I anticipated some 'pedophelia!!!' Cries for this video. All I can say is Maddie and Shia are two of the only actors I felt could play
"These two warring 'sia' self states. (sic)"
Tagged in Shia LaBeouf Sia