12/15/2014 12:08 EST | Updated 02/14/2015 05:59 EST

Samuel L. Jackson challenges stars to sing against 'racist police'

Pulp Fiction and Snakes on a Plane star Samuel L. Jackson is calling on celebrities who supported this summer's Ice Bucket Challenge to unite to stop what he calls "the racist police."

"All you celebrities out there who poured ice water on your head, here's a chance to do something else," challenged the 65-year-old actor in a video posted on his personal Facebook page Saturday.

The Ice Bucket Challenge, which inspired thousands of people to dump buckets of ice and water on their heads, or donate money to ALS research, helped raise more than $16.2 million in Canada alone.

- On mobile? Watch Jackson's video challenge here

Instead of enduring an icy deluge, Jackson wants supporters to post clips of themselves singing the We Ain’t Gonna Stop, 'Till People Are Free song.

The 47-second video includes Jackson's rendition of the song, which references the last words of Eric Garner, the 43-year-old man who died in July after being put in a chokehold by a New York City police officer.

I can hear my neighbour cryin’ ‘I can’t breathe’
Now I’m in the struggle and I can’t leave.
Callin’ out the violence of the racist police.
We ain’t gonna stop, till people are free.
We ain’t gonna stop, till people are free.

"Come on, sing it out," said Jackson in his appeal, which came on the same day tens of thousands of protesters gathered across the U.S. and Canada to demonstrate against racism and police brutality.

Unarmed black men killed by police like Garner, and Michael Brown, from Ferguson, Mo., were front of mind as crowds gathered in Washington, New York and San Francisco. Hundreds more held a similar demonstration in Toronto. 

The stars of the new civil rights movie Selma spoke out against police brutality at the film's premiere Sunday night in New York.

A number of cast members sported T-shirts reading "I Can't Breathe," while others raised their hands on the red carpet in a "don't shoot" gesture – an expression that became widely used during protests against police in Ferguson.