Rio Olympics 2016: US athlete shamed online for wearing Canada hat

Canada's Brianne Eaton Theisen is encouraged by her husband Ashton Eaton of the United States, second right. Photo / AP

Star US decathlete Ashton Eaton has come under fire from Olympic viewers after wearing a Canada hat while cheering on his wife, Canadian heptathlete Brianne Theisen-Eaton.

Defending Olympic champion Eaton was seen sporting a red "Canada" baseball cap at the Olympic track meet on Saturday as Theisen-Eaton began her quest for a medal.

Have I not represented USA well? Yet u demand more. Ur respect is hard earned. I support the country that produced my wife;who ru2 shame me?

— Ashton Eaton (@AshtonJEaton) August 13, 2016

He's since come under fire on social media, labelled a traitor, accused of breaking United States supporters' hearts and criticised for not finding a way of supporting his wife other than adopting another country's colours.

Eaton was forced to hit back via his own Twitter account.

"Have I not represented USA well? Yet u demand more. Ur respect is hard earned. I support the country that produced my wife; who ru2 shame me?" he tweeted.

"Are your grandparents from another country? Will your grandchildren be? What then? Hopefully you'll adopt a more reasonable view."

I've never seen Ashton Eaton mad until tonight. Oh Lord. What have u guys done.

That's his WIFE. He made a vow to support her- for Life

— Lolo Jones (@lolojones) August 13, 2016

Many users also jumped to his defence, applauding him for being a supportive husband.

Athletics Canada then joined the conversation, backing Eaton, in true Olympic spirit.

"We appreciate the support for your wife, & we're cool with Bri supporting (the US) when you compete," the organisation tweeted.