Miley Cyrus and Liam Hemsworth attended an unusual birthday party thrown by the Hunger Games star's sister-in-law, Samantha Hemsworth, on Saturday (13 August). The shindig saw guests wear golden outfits and indulge in some body panting. The highlight of the party was a life-size statue of a golden horse, which the invitees posed on.

Photos published on news.com.au showed the Wrecking Ball hit-maker in a gold-coloured basketball jersey posing next to the statue. Another snap saw the 26-year-old actor smiling for the cameras while sporting a black tank top paired with golden shorts. However, the most peculiar photo from the party was that of a guest applying paint on another guest's buttocks.

The party was also attended by Liam's brother Luke, pro surfer Kelly Slater and Flaming Lips frontman Wayne Coyne.

According to Coyne's photo shared on Instagram, the gold-themed party got weirder after 5am as guest painted each others' buttocks and drew butterflies on paper. He has captioned the photo: "Painting butterflies with butts at 5:00 am.. Yep .. @katyweaver@mileycyrus @liamhemsworth@addyjames @michelechantel."

Coyne also shared a photo with Cyrus. In the photo, Coyne is wearing a gold ram horns with his hands raised while seated on the life-size statue of the horse.

"Gold party with the fam!!!! @mileycyrus @katyweaver @addyjames @michelechantel @stong @liamhemsworth .. Yeah those are gold ram horns I'm Wearin," 55-year-old singer captioned the photo.

However, it unclear whether Cyrus and Hemsworth got involved in the buttocks painting contest.

Gold party with the fam!!!! @mileycyrus @katyweaver @addyjames @michelechantel @stong @liamhemsworth .. Yeah those are gold ram horns I'm Wearin ...

A photo posted by Wayne Coyne (@waynecoyne5) on

Cyrus and Hemsworth got back together in December 2015 after ending their engagement in 2013. The couple first met on the set of the movie The Last Song 2009.

Miley Cyrus Liam Hemsworth
Miley Cyrus and Liam Hemsworth met on the sets of movie The Last Song in 2009 Reuters