Liam Hemsworth has urged his Instagram followers in Australia to support same-sex marriage.

The 27-year-old actor has thrown his support behind the campaign to legalise same-sex marriage Down Under, imploring his social media followers to ''vote yes'' in the country's equality vote.

Alongside a snap of his homeland covered in the colours of the rainbow flag, Liam wrote: ''I personally do not believe that same sex marriage should come down to a vote. I believe it's a HUMAN RIGHT to be able to marry the person you love regardless of gender. To all the Australians that care about equality and human rights please say YES to same sex marriage. Let's not be silly about this. Vote YES for same sex marriage in Australia. (sic)''

Australians have been given until November 7 to vote on the issue, which is ultimately set to be decided in the country's parliament.

But the yes movement has another high-profile supporter in the form of Liam's fiancee, Miley Cyrus.

The chart-topping star is a well-known advocate for gay rights and she has actively supported the community through her own organisation, The Hippy Foundation.

Speaking about the issue back in 2016, Miley explained: ''My whole life, I didn't understand my own gender and my own sexuality.

''I always hated the word 'bisexual,' because that's even putting me in a box. I don't ever think about someone being a boy or someone being a girl. Also, my nipple pasties and s**t never felt sexualised to me.''

Meanwhile, American talk show host Ellen Degeneres has also weighed in on the discussion, telling her Australian followers to support the yes movement.

Ellen - who married actress Portia De Rossi in 2008 - wrote on Twitter: ''Should the law be changed to allow same-sex couples to marry?'' Yes, it should. (Let's do this, Australia.) (sic)''