Zac Efron says he "bounced back quick" after reportedly being struck down with a serious infection.
The Greatest Showman star was filming Killing Zac Efron in Papua New Guinea at the weekend, when it was claimed he contracted a "form of typhoid or similar bacterial infection".
Zac was believed to have been rushed to hospital in Brisbane, Australia, in what was called a "life-or-death flight".
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He was then reported to have been admitted to the private St Andrews War Memorial Hospital "in a stable condition".
After receiving treatment for a number of days, Efron was given the all clear to fly back to his home in the United States.
And now, the High School Musical star has broken his silence and thanked everyone for their well-wishes, though he did not comment on what caused him to be poorly.
Alongside a picture of the actor with a group of local children, he wrote on Instagram: "Very thankful to everyone who has reached out.
"I did get sick in Papua New Guinea but I bounced back quick and finished an amazing 3 weeks in P.N.G.
"I'm home for the holidays with my friends and family.
"Thanks for all the love and concern, see you in 2020!"
Medical Rescue director Dr Glenn McKay was unable to comment specifically but did confirm that his team "retrieved a US citizen in his 30s from PNG to Brisbane for medical attention in Australia".
Efron's new show will follow the 32-year-old actor as he heads to the jungle on a remote island for 21 days and will be "off the grid" with nothing but basic gear and a guide partner.
Efron said: "I tend to thrive under extreme circumstances and seek out opportunities that challenge me on every level. I am excited to explore any uncharted territory and discover what unexpected adventure awaits."
The programme is set to air on short-form mobile video platform Quibi, which launches in April.
Efron has previous experience in the wild as in 2014, he appeared as a guest on Running Wild with Bear Grylls, where the two jumped out of a helicopter, trudged over rough terrain in the Catskills, and ate an earthworm.
He will also executive produce the new series with Zero Point Zero and Ninjas Runnin' Wild.