Sarah Silverman, Mark Ruffalo, and more celebrities strip naked for this special cause

Sarah Silverman, Mark Ruffalo, and a handful of other celebrities stripped down to grab the attention of American voters.

In the video released on Wednesday by nonpartisan organisation RepresentUs, the famous faces were seen without their clothes as they warned the voters about "naked ballot," an issue in some of the states in the US where a postal vote is classed as void if instructions about putting them in two envelopes are not followed.

The star-studded video began with Chris Rock telling people that he is naked before it cuts onto Tiffany Haddish who makes the same declaration. Amy Schumer and Josh Gad are the next celebrities to appear nude in the Public Service announcement, followed by Sarah Silverman who speaks into the camera while covering her breasts with her hands.

The frame then shifts to Borat, who is the only one dressed in the video, and then back again to naked celebrities including Mark Ruffalo, Kerry Washington, Chelsea Handler, Ryan Bathe, and Naomi Campbell. Even Silverman's dad Donald Silverman strips down to lend voice for the important cause.

In the video, the celebrities discussed the postal voting system and urged people to read the instructions carefully, while explaining the "naked ballot" in 16 states including Pennsylvania where postal votes are placed into two envelopes and will be deemed void if not delivered in this way.

"If you don't do exactly as I tell you, then your ballot could get thrown out," said Silverman.

The stars also urged the viewers to submit their vote as soon as possible, before concluding the video by urging everyone to participate in the upcoming elections in November. "Take your clothes off and vote," Amy said, while Chelsea Handler noted: "Everyone's voice matters in this election."

The clip ended with Silverman saying "America needs you," before removing her hands covering her breasts to perform a salute.

The celebs took to their social media accounts to spread the video. "We made a PSA to help you make sure your mail-in vote counts," Silverman tweeted, while Chelsea Handler wrote: "Voters! #NakedBallots won't be counted. Make sure to follow instructions carefully to ensure your voice is heard."