An event invitation accidentally sent out by the U.S. Embassy in Australia went viral Monday for featuring a well-known meme of a cat wearing a Cookie Monster onesie.

The note, entitled "meeting," was disseminated on behalf of the State Department to an unknown number of recipients, according to the Australian Associated Press.

The body of the email included the image of a cat lounging in the blue costume, while holding a plate of chocolate chip cookies. It also included the heading, "cat pajama-jam." The invitation was quickly retracted.

"Sorry to disappoint those of you who were hoping to attend this 'cat pajama-jam' party, but such an event falls well outside our area of expertise," U.S. Mission to Australia public affairs counselor Gavin Sundwall wrote in a followup note.

"It was a training error made by one of our new staff testing out our email newsletter platform," Sundwall said, adding that additional controls would be introduced to the program to avoid similar embarrassments.

The U.S. Embassy in New Zealand was quick to poke fun at the mistake on social media.

"We are actually LOLing here in NZ," diplomatic staff posted on Twitter, along with a graphic of a cat frantically typing on a computer.

Australia has been without an official U.S. ambassador since September 2016. President Trump's original nominee Navy Adm. Harry Harris was reassigned in April to South Korea.