Actor Zac Efron has reportedly been flown to Australia for urgent medical assistance after contracting an illness that threatened his life.

On Sunday, TheDaily Telegraph reported that the 32-year-old actor was filming a documentary series in Papua New Guinea when he suffered a “life-or-death medical emergency”.

It is understood he was transported via plane to Brisbane Airport last week, before Christmas Day, with a bacterial infection.

He was treated at St Andrews War Memorial Hospital in Spring Hill, the publication reports, and was permitted to return home to America on Christmas Eve.

Zac Efron pictured with his tour guide Cyril Tara in Papua New Guinea. Image: Facebook.

Upon arriving, Efron, who rose to fame after starring inHigh School Musical, was in a "stable" condition and remained in hospital for a number of days while he recovered.

On Monday, the 32-year-old shared a short statement to Instagram, thanking his fans for all their "love and concern" following the incident.

"Very thankful to everyone who has reached out," Efron wrote.

"I did get sick in Papua New Guinea but I bounced back quick and finished an amazing three weeks in P.N.G.," he added.

"I'm home for the holidays with my friends and family. See you in 2020!"

The TV series the actor was filming in Papua New Guinea is calledKilling Zac Efron.

The show is described as following the Hollywood star as he goes "deep into the jungles of a remote, dangerous island to carve his own name in expedition history."

"Zac is going all-in, falling off the grid for 21 days with nothing but basic gear, a guide partner and a will to survive," the show's synopsis states. The programme, also executive produced by Efron, will be available on Quibi, a new streaming service for phones.

"I tend to thrive under extreme circumstances and seek out opportunities that challenge me on every level," Efron said in a statement aboutKilling Zac Efronin November.

"I am excited to explore any uncharted territory and discover what unexpected adventure awaits!"

Efron's tour guide Cyril Tara has uploaded a number of photos of himself with the Hollywood actor to his Facebook, documenting their adventures together.

Most recently, Efron has gained critical claim for his role as Ted Bundy - one of America's most notorious serial killers - in the 2019 Netflix movieExtremely Wicked, Shockingly Evil and Vile.

Other notable films he has starred in since his wildly-successful role inHigh School MusicalincludeBaywatchin 2017,The Greatest Showmanin 2017,Dirty Grandpain 2016 andNeighboursin 2014.

His new showKilling Zac Efronis set to air on Quibi in April 2020.

Feature Image: Facebook.

This article was originally published on December 29, 2019, and was updated on December 30, 2019.

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