If you were retiring from a high-stress job before the age of 50, you'd probably be pretty happy too.

Especially if that job was prime minister of the U.K., and, you were responsible for a referendum where Britons voted to leave the E.U., wreaking havoc on the country's economy with no clear end in sight.

But maybe David Cameron could have done a better job of hiding his relief after announcing he would be replaced by a successor by Wednesday.

An instantly viral video making the rounds on Twitter shows the soon-to-be former PM walking away from the podium and into 10 Downing St. after making the announcement Monday. Unaware that his microphone is still on, he sings a lyricless little ditty ("doo doo doo doo") before stepping inside and saying, "Right. Good."

Twitter users had a great time mocking Cameron's not-so-private celebratory tune.

Some speculated about what he was singing and what it meant.

Cameron haters found the moment symbolic.

A BBC journalist who posted the video on Twitter joked about its virality.

To be fair, Cameron isn't the first singing world leader we've seen. Maybe with those pipes, he could join the Van Cats.

Harper sings Sweet Child O' Mine1:07