The photo was met with shock and disgust from Hanks' Aussie fans who felt obliged to educate the actor about the correct Vegemite to toast ratio.
"Gee, that's a lot of Vegemite," tweeted ABC News Breakfast host Michael Rowland in response.
Some of the other replies Hanks received included:
• "Oh my, Mr Hanks, not even the bravest Aussie would put THAT much Vegemite on a piece of toast!"
• "Vegemite is not nutella. You want to spread it thinly and mix it in with the melted butter until it looks like a poorly maintained public toilet. That's the sweet spot."
• "Life is like a tube of Vegemite. Don't try it all at once."
• "Corona won't kill you but that amount of Vegemite will!"
• "Maybe corona affects your tastebuds because that's wayyyyy too much Vegemite buddy."
• "That amount of Vegemite would put anyone in hospital. I developed a yeast infection just looking at this picture. (Also, best wishes for a speedy recovery.)"
Aussie actor Daniel MacPherson was firmly in Hanks' corner, tweeting his support to the legendary star: "Thicker the spread, less time in bed".
Hanks' Vegemite update comes after the actor and his wife announced on Friday they were making a Spotify playlist for "people self-quarantining" and asked for song suggestions and title for the mix.
Hours later, Wilson shared the final product.
Every song in the playlist is a cheeky nod to their current situation - and includes the likes of Richard Marx's Right Here Waiting, Lonely People by America, Eric Carmen's All By Myself and Queen's I Want To Break Free.
That post came after Hanks gave fans a reassuring update a day after he and wife Rita Wilson announced that they'd both been diagnosed with coronavirus.
The A-list pair, currently staying in Australia as Hanks films an Elvis Presley biopic on the Gold Coast, said they were "taking it one day at a time".
"Rita Wilson and I want to thank everyone here Down Under who are taking such good care of us," Hanks wrote in a note posted to his official Twitter and Instagram accounts alongside a selfie of the pair in good spirits.
"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.
"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?"
Hanks finished by paraphrasing one of his most famous big screen lines, from the 1992 hit A League of Their Own: "Remember, despite all the current events, there is no crying in baseball."
