US Embassy 'sorry to disappoint' after Cookie Monster cat pyjama-party invitation sent out accidentally

The US Embassy in Australia has apologised after it inadvertently spammed computers with a photo of a cat dressed in Cookie Monster pyjamas, holding a plate of biscuits.

The email, titled "meeting", featured a photo of a tabby cat wearing a blue Cookie Monster outfit was reportedly sent by mistake as part of a training exercise - distributed as fake meeting invitation.

In addition to the picture there was a section of text in Latin - further confusing recipients.

US Mission to Australia public affairs counsellor Gavin Sundwall apologised on behalf of the US State Department, saying that there would sadly be no such pyjama party.

"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," he wrote in a light-hearted email two days after the original was sent.

"It was a training error made by one of our new staff testing out our email newsletter platform."

Mr Sundwall said "strong new management controls" would be added to prevent a repeat of the mistake.

A number of cat owners took to twitter to show their disappointment that the pyjama party would not be going ahead.