Australia’s third showing at Eurovision was overshadowed by a serial prankster draped in an Aussie flag, who stormed the stage to bare his backside to the watching world.

As two Australians competed in the 2017 global song contest, the surprise flasher stole the show as he interrupted last year’s winner Jamala’s half-time performance by waving his rear end to the crowd, as votes were being tallied.

It was initially thought the streaker was an Australian, but it was later confirmed the man was Vitalii Sediuk – a Ukrainian journalist and self-described prankster.

He has a long list of accosting celebrities, with victims including supermodel Gigi Hadid, Will Smith, Brad Pitt and Leonardo DiCaprio.

Most famously, Sediuk attacked Kim Kardashian in September last year when he tried to kiss her famed derrière.

At the 2013 Grammy Awards, Sediuk rushed the stage and accepted an award on Adele’s behalf.

On Sunday morning (AEST) at Eurovision, he was quickly crash-tackled off the stage by security and the show’s hosts made no mention of the incident.

The show’s often bizarre highlights included enthusiastic yodellers from Romania, a boy band in Hawaiian shirts from Spain and a man in a gorilla suit from Italy, but it was Sediuk’s antics that got the most attention.

"Whose idea was it to invite Australians?!" #SBSEurovision #streaker #eurovision pic.twitter.com/Ynp0KbaAGy

— Michael Smyth (@MichaelSmyth_) May 13, 2017

Anyone seen my head? It's gone missing from laughing my head off. #aus #Eurovision #streaker

— Not a cat 🇪🇺 (@CatTimon) May 13, 2017

https://twitter.com/MissJennifer/status/863519020544339968?ref_src=twsrc%5Etfw&ref_url=http%3A%2F%2Fstorify.com%2Fabcnews%2Faussie-streaker-invades-eurovision-stage%2Fembed%3Fheader%3Dnone%26border%3Dfalse

Australia’s official competitor Isaiah Firebrace came in a respectable ninth place with his song Don’t Come Easy.

Firebrace recovered after a vocal hiccup in the semi-final to deliver a soulful rendition that drew plenty of compliments on social media and from the judges.

English television presenter Graham Norton complimented him on his “ballad-powered eyebrows”.

Isaiah Firebrace performs his song Don’t Come Easy. Photo: AAP

Firebrace’s final effort placed him in fourth with the juries from 26 different counties counting for 50 per cent of the vote, then slipped to ninth once fan votes were collated.

He and Belgium’s entrant, Blanche, were the youngest competitors at the Eurovision Song Contest at 17.

Click the arrows below to view our gallery:

Jacques Houdek, representing Croatia, blasts his ballad My Friend. Photo: Getty

Don't even bother: Armenia's Artsvik waves off flames during the song Fly With Me. Photo: Getty

Spanish singer Manel Navarro brought the beach vibes with his song Do It For Your Lover. Photo: Getty

Man on the moon: Austria's Nathan Trent Photo: Getty

Greece's Demy rendition of This Is Love came with plenty of skin. Photo: Getty

Musician JOWST smashing the drums for Norway. Photo: Getty

Can you ever have too much gold: United Kingdom singer Lucie Jones during her golden performance, Never Give Up On You. Photo: Getty

What's Eurovision without a cannon?: Romania's Alex Florea poses atop of a cannon during his performance. Photo: Getty

France's singer Alma delivers her song Requiem in style. Photo: Getty

Winner Salvador Sobral from Portugal poses with the Eurovision trophy, on his head. Photo: Getty

Because why wouldn't Italy's entrant Francesco Gabbani sing alongside a gorilla? Photo: Getty

Dihaj for Azebaijan performed her song Skeletons with a chalk background, ladder and a man oddly wearing a horse mask. Photo: Getty

Australia's Isaiah Firebrace performs his song Don't Come Easy. Photo: Getty

Anja Nissen hits a high note with her song Where I Am. Photo AAP

The Eurovision prankster wearing an Australian flag moons the crowd. Photo: Twitter

Meanwhile, fellow Australian Anja Nissen, who represented Denmark, came 20th out of 26 at the grand final in Kiev.

The former Voice Australia winner delivered a flawless performance of the ballad Where I Am, but could only manage 77 votes.

Nissen, 21, grew up in Sydney’s Blue Mountains, and had hoped she could rally support from both Australia and Denmark, only to see Australia’s 12 votes given to Britain.

Wearing a long flowing red dress, Nissen was the picture of confidence as she performed in front of a 50-second cascade of fireworks, the longest pyrotechnic display in Eurovision history.

Anja Nissen hits a high note with her song Where I Am. Photo: AAP

Portugal’s Salvador Sobral won the Eurovision crown with his beautiful orchestral ballad Amar Pelos Dois, written by his sister.

After being named the winner, Sobral spoke out against ‘fast food music’ and its impact on the industry.

“I want to say that we live in a world of disposable music and I think this could be a victory for music with people that make music that actually means something,” he said.

“So let’s try to change this and bring music back which is really what matters.”

The final results: Portugal was the hands-down winner. Photo: Eurovision