"Hello folks. @ritawilson and I want to thank everyone here Down Under who are taking such good care of us," the two-time Oscar winner posted on Instagram. "We have Covid-19 and are in isolation so we do not spread it to anyone else. There are those for whom it could lead to a very serious illness. We are taking it one-day-at-a-time."
He added, "There are things we can all do to get through this by following the advice of experts and taking care of ourselves and each other, no? Remember, despite all the current events, there is no crying in baseball."
Hanks, 63, posted Wednesday on Instagram that while in Australia, he and Wilson came down with symptoms resembling a cold, as well as body aches and slight fevers.
"To play things right, as is needed in the world right now, we were tested for the Coronavirus, and were found to be positive," Hanks wrote.
The actor wrote that he and Wilson, an actor and a producer, "will be tested, observed, and isolated for as long as public health and safety requires."
Hanks is in Australia for preproduction of an untitled film about Elvis Presley, according to the entertainment website Deadline.
Download the NBC News app for full coverage of the coronavirus outbreak
Hanks in 2013 revealed on “The Late Show with David Letterman” that he had been diagnosed with type 2 diabetes. The actor said at the time that it was controllable.
The Centers for Disease Control and Prevention says on its website that older adults and people with chronic health conditions such as diabetes or heart or lung disease are thought to be at higher risk of getting seriously ill from COVID-19.
In a video posted to his Instagram account, Hanks' son, Chet, said his parents were doing OK.
"I just got off the phone with them. They both are fine. They’re not even that sick," he said. "They’re not worried about it, they’re not tripping, but they’re going through the necessary health precautions, obviously."
Chet Hanks added that he appreciated everyone’s concern and good wishes “but I think it’s all going to be all right."
"Everybody stay safe out there," he added.