Sia is known to be an unconventional artist. She chooses to sing without facing the audience, and she made sure that her contract for her album didn't include promotional efforts from her like touring. 

Despite being a great singer and a songwriter for top pop artists in the music industry such as Rihanna, Katy Perry and Beyonce, the 39-year-old musician is known to shy away from fame and popularity. But one thing cannot be ignored, the art in Sia's live performances and music videos speaks volumes about her musical artistry. 

Sia's "Chandelier" was nominated for Record of the Year at the recently held 2015 Grammy Awards. But apart from the song, the artsy music video has already garnered over 560 million views to date. The artist isn't shown in the music video; instead, the highlight is on the young "Dance Moms" dancer Maddie Ziegler. 

In Sia's next music video "Elastic Heart," Maddie is seen dancing again, but this time, she dances with actor Shia LeBeouf. The music artist co-directed the video herself and her unique artistry shows once again.

But seeing the 12-year-old dancer in two music videos prompted questions if she would be a permanent fixture in Sia's music videos. The singer answered the questions directly. In a behind-the-scenes video for "Elastic Heart," Sia revealed that Maddie is part of a trilogy. 

"The 'Elastic Heart' is part of a trilogy because we had such an amazing time making that video we decided we wanted to do a trilogy," Sia said. "It's so hard, dancing is so hard... I was watching Dance Moms and I saw Maddie [Ziegler] and I thought she was incredible. I cried." 

Sia was surprised at the effect of Maddie's dancing. She deemed that if it had an effect like that with her, it would also have the same powerful effect on others. She was right. Fans and non-fans of the singer have come to appreciate the young dancer's emotional interpretive dance.  

Meanwhile, Maddie shared her experiences in doing both music videos.

When she spoke with Entertainment Weekly, she said, "It was amazing. The story behind it is a lot different than the 'Chandelier' video. When I did 'Elastic Heart' obviously it was the same concept with my leotard and wig, but we were really dirty. I'm going to be honest with you, it was the most dirty I've ever been in my whole entire life. My shower was disgusting, and the water was like... ugh. I was disgusted." 

What about dancing with Shia? After all, the "Transformers" actor is not a dancer. Maddie said that Shia took her and her mother out to eat so they could get to know each other before dancing. 

"You can't just walk in and be like, 'Hey, let's start dancing with each other!'" she said. "He actually did really well, he did. He wasn't a bad dancer at all. For him, it was mainly fighting, and acting, and running around. And screaming." 

So, there's only one video left in the Sia-Maddie trilogy. Which song could it be?