Kiwi actor Sam Humphrey. Photo / Getty Images

Kiwi-born actor Sam Humphrey is in critical condition and fighting for his life as he prepares to undergo a very risky surgery.

The 24-year-old, who played General Tom Thumb in The Greatest Showman, is suffering from complications with Crohn's disease, a chronic inflammatory bowel disease.

His condition has been made worse by his skeletal dysplasia, the DailyMail reports.

"He is currently under the care of some of the best doctors in the world at Cedars Sinai and is undergoing high-risk corrective surgery," his family said in a statement.

The star has already been in the hospital for "weeks," according to TMZ.

Last year's The Greatest Showman was the Kiwi's first big screen role.

The film — which also starred Hugh Jackman, Michelle Williams, Zac Efron and Zendaya — was nominated for Best Original Song at this year's Oscars.

He has also appeared in several episodes of Australian soap Neighbours, as well as a number of theater productions.

The 4'2" star was born with a rare genetic disorder called acrodysplasia, which prevents proper formation of parts of the skeleton.

Coupled with his childhood diagnosis of Crohn's disease, he spent much of his early life in and out of hospitals; doctors did not expect him to reach his teen years, let alone adulthood.

He previously revealed he had attempted suicide several times, but eventually overcame his disabilities to successfully pursue his dream to become an actor.

The real life General Tom Thumb — whose real name was Charles Stratton — was a famous dwarf performer under circus pioneer P.T. Barnum.