Madonna has followed in Katy Perry's footsteps by posting a naked selfie on Instagram to promote voting in the US election.

Madonna's topless selfie

Madonna's topless selfie

The 'Dark Horse' stripped off naked for a Funny Or Die sketch to "help change the world" and encourage people to get out of their houses and vote for the new American President on November 8.

Madonna, 58, was watching Katy's stunt and has now posted her own nude selfie on Instagram, stating that she's "with Katy Perry".

The caption reads: "Im voting naked with Katy Perry!! Vote for Hillary. She's the Best we got!. Nude Voting series # 1 (sic)"

It is unclear as of yet what the 'Like a Virgin' singer means by "series number 1", but it could mean that there are more nude selfies on the way as the US edges closer to election day.

For the 'Papa Don't Preach' hitmaker it isn't be the first time she's shed her clothes to encourage people to vote.. The pop megastar famously draped an American flag over her bikini-clad body for a commercial that aired on MTV, kicking off the first 'Rock the Vote' drive in 1990.

In the video, the blonde beauty altered the lyrics to her hit single 'Vogue', and says: "Doctor King, Malcolm X/Freedom of speech is as good as sex/Abe Lincoln, Jefferson Tom/They didn't need the atomic bomb."

At the end of the commercial, Madonna told viewers: "If you don't vote, you're going to get a spanking!"

In the Funny Or Die sketch, 31-year-old Katy is seen telling viewers you can turn up to vote in whatever you want, before getting arrested for stripping off naked at a polling station.