Actress Kristen Bell has signed on to sing the closing song for a new environmental documentary.

Tell Me How Long was composed by Dan Romer and Teddy Geiger for the documentary, Chasing Coral. The film focuses on climate change and the coral reefs bleaching crisis.

“I was moved and inspired by Chasing Coral and its message of hope for our planet’s future,” the Frozen star says. “I feel a responsibility to care for the earth in whatever way I can and I was honored to lend my voice to the original song.

"As we strive to make a better world for our children, I hope this film will ignite real action in advancing climate solutions in our global communities.”

The documentary, directed by Jeff Orlowski, will be released on streaming service Netflix later this month (Jul17).