It means the Qantas Wallabies will be able to attempt to emulate the class of 1984, who swept through the UK and Ireland to complete a Grand Slam of victories over England, Scotland, Ireland and Wales. They will also play Italy in a tough trip around five European capital cities.
The Alan Jones-coached and Andrew Slack-led Wallabies of 1984 are the only side among the eight Australian outfits that have attempted a Grand Slam, to have achieved the feat.
The additional fixture against the RBS 6 Nations champions, at the Millennium Stadium on 30 November, will be the 10th in five years between the two nations - with the Qantas Wallabies coming out on top in the last eight.
The game in Cardiff will be the Wallabies ninth visit to the Welsh capital in as many years and they will be looking to equal the record of nine successive wins in the series. The Millennium Stadium match will close a tour which starts in London against England on 2 November and then runs through Tests against Italy, Ireland and Scotland on the following weekends.
James Horwill, who captained the Wallabies at that tournament, and scored a try in the 33-12 success that kicked off the current winning sequence, welcomed the news of both the Grand Slam and another further playing opportunity in the Welsh capital.
Wallaby skipper James Horwill was a member of the last Australian side to attempt a Grand Slam , four years ago. He says the lessons of that tour will be invaluable for this year's assignment.
"The Grand Slam is a big thing and is something the players will look forward to and be excited about once they've earned the right to make that tour," said Horwill.
"You can't take participation for granted, and no one will, but it will be a great way to finish what is going to be one of the biggest years in the history of the game in Australia."
In 2009, Australia opened its Grand Slam attempt with a second consecutive win over England at Twickenham, but had the bid thwarted a week later in Dublin when an 80th minute try by Brian O'Driscoll in his 100th Test secured Ireland a 20-20 draw at Croke Park.
Australia fell 9-8 to Scotland a week later in Edinburgh, but bounced back from that disappointment to overpower a confident Wales 33-12 in the final game of the tour.
"There's a good core of guys in the squad now who were on that trip. Having the Grand Slam opportunity taken away in the final minute in Dublin like it was, wasn't the reason we lost the next week in Scotland.
"But there's no doubt that it's dangerous if it [the Grand Slam possibility] becomes too much of a focus. With so much rugby to play between now and then, I don't think it will be."