Chris Hemsworth has revealed his father was recently diagnosed with early-onset Alzheimer’s and he hopes his latest project will help fight the disease.

Hemsworth – who three years ago discovered he has a high risk of also developing Alzheimer’s disease – on Friday posted an emotional trailer for his National Geographic documentary A Road Trip to Remember.

The special will follow Hemsworth, 42, and his father Craig, 70, on a motorcycle “road trip back in time’ from Melbourne and into the Northern Territory.

“I want to do everything I can to help him,” Hemsworth says in the trailer.

“Turns out this experience could help fight the disease.”

In his post accompanying the trailer on X, Hemsworth said he and his father had always spoken about taking a trip back to the NT, where his family had lived years ago.

“But we had never been able to set aside the time to actually do it,” he says.

“More recently the idea of taking that road trip re-emerged with more pressing importance.”

Hemsworth spent much of his early childhood in NT. Photo: National Geographic

National Geographic said the idea of the road trip, and documentary, was to rekindle memories, “exploring the effective science of connection, community and nostalgia – crucial but often overlooked tools in protecting brain health”.

Dr Suraj Samtani, a dementia specialist and clinical psychologist at the University of NSW Centre for Healthy Brain Ageing, worked with producers in collaboration with the Hemsworth family over the course of a year.

Samtani’s research, along with a recent global study of more than 40,000 people in 14 countries, found that those who kept up regular social interactions cut their risk of developing dementia in half, with evidence showing that strong social connections can even slow cognitive decline after diagnosis.

National Geographic said the documentary explores:

• Reminiscence therapy – revisiting past experiences by talking to someone about them, using objects from the past (such as photos or home videos), or visiting places from the past is a great way to boost cognition.
• Social connection – regular interactions, such as talking with a friend or having a confidante, are shown to reduce the risk of early mortality.
• Social bridging – participating in wider community activities, like volunteering or group walks, is linked to slower rates of cognitive decline.

While filming the second season of his Disney + series Limitless in 2022, Hemsworth had genetic testing that revealed he is eight to 10 times more likely than the average person to develop Alzheimer’s disease.

The APOE4 gene is closely associated with Alzheimer’s disease and 25 per cent of the general population hold one copy of it.

Hemsworth was told that he has one copy from his mother, and a second from his father, putting him among the rare 3 per cent of people who carry two copies of the gene.

“The idea that I won’t be able to remember the life I experienced, or my wife, my kids, is probably my biggest fear,” Hemsworth said at the time.

Hemsworth, the second of three now-famous sons – including actor brothers Luke and Liam – was born in Melbourne in 1983, before moving with his family for a time to the isolated town of Bulman in the Northern Territory.

Craig Hemsworth worked a social services counsellor while his mother Leonie was an English teacher.

“My earliest memories were on the cattle stations up in the Outback, and then we moved back to Melbourne and then back out there and then back again,” Hemsworth said.

Chris Hemsworth: A Road Trip to Remember screens on Disney + from  November 24.