Fans of Zac Efron were worried when reports surfaced that the actor had been evacuated by plane to a hospital in Australia.

The 32-year-old, who was filming survival show Killing Zac Efron in Papua New Guinea, was said to have contracted a deadly typhoid or similar bacterial infection.

On Sunday (Dec 29), he calmed nerves when he posted 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 three 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."

His reassuring update has drawn more than one million likes.

He was warded in a Brisbane hospital for several days before the doctors allowed him to fly back to the United States on Christmas Eve.

When the show was announced last month, he said: "I am excited to explore any uncharted territory and discover what unexpected adventure awaits."