Zoe Saldana & Julianne Moore Bring Sia's Heartbreaking Song To Life

Sia has always been an artist and performer unlike any other. When she performs live, she is often hiding behind her huge wig, which has become so synonymous with her public image that it's headline news when she is seen without it. And she doesn't even appear in her own music videos. Instead, she enlists the help and talent of a range of celebrities (remember Shia LaBeouf in "Elastic Heart"?) to translate the song into dance with their own physical expression.

With her latest song, "Free Me," Sia does just that — and more. The music video for the track features Oscar-winning actress Julianne Moore and actress Zoe Saldana in a heartbreaking and beautiful story about an expecting mother learning she has HIV and could pass it on to her unborn child if she goes untreated. Moore narrates the video, and Saldana acts as a the protagonist, crying and dancing as she acts out the story behind the song. Sia released the video and song with the Abzyme Research Foundation to benefit the #endHIV campaign. It also features choreographer from her longtime collaborator, Ryan Heffington. All proceeds for the song, which is available digitally on Friday June 9, will go to support trials for a vaccine, the singer wrote on Twitter.

Watching the video is an emotional experience, considering the impressive performance from Saldana, who is a mother of three, and moving lyrics from Sia: "Free me from the shame I am running from/ I am lost and I am calling." Sia is known for her poignant music videos, but this one may be her most impassioned and relevant one yet.