Sia has released a new song called The Greatest, which features old friend Kendrick Lamar and the return of dancer Maddie Ziegler in the video – a moving tribute to the Orlando shooting.

The Chandelier and Elastic Heart singer dropped the single unexpectedly, with Kendrick Lamar singing the verse “I transform with pressure, I’m hands-on with effort/ I fell twice before, my bounce back was special/ Letdowns will get you and the critics will test you/ But the strongest survive another scar may bless you.”

The video has a dance sequence featuring the pop star’s friend Maddie Ziegler. Although the video does not feature Lamar’s verse, that version of the song can be streamed via Spotify. Sia released her most recent album This is Acting in January. Back in July, Sia reached her first Billboard Hot 100 No. 1 hit featuring Sean Paul, with Cheap Thrills.

Directed by Sia and Daniel Askill, the video opens with shots of a distressed Ziegler, who wipes paint down her face, in the colours of the rainbow – a symbol for the Gay Pride movement. She is with a troupe of kids, who seem to be locked behind bars. Ziegler and 49 other dancers stand in for those who were killed the night of the Orlando shooting, using a range of expressive hand and facial gestures.

The song and video are a tribute to the victims of the Pulse nightclub massacre in Orlando that took the lives of 49 members of the LGBT community. As The Greatest starts playing, Ziegler frees the kids and leads them on a choreographed run throughout the house.

Watch the video (which doesn’t feature Kendrick Lamar) below.