The Duke of Edinburgh entered into the spirit of the occasion and flipped a steak sizzling on a grill as he joined cooks attempting to hold a record-breaking barbecue.
The event was the last engagement in the Queen and Duke's 11-day tour of Australia, and the monarch told the crowds: "We have been overwhelmed by your kindness and support.
"Once again we will return to the United Kingdom with fond memories of our time here and the warm Australian welcome we have received on our 16th visit to this beautiful country."
The Queen has received a rapturous welcome during her tour, and Perth residents followed the national mood and turned out in their tens of thousands for a final glimpse of the Royal couple.
The visit has already secured its place in history as yesterday Prime Minister David Cameron, in Perth for a Commonwealth leaders' summit, secured the agreement of the 15 nations where the Queen is head of state for a change in the rules of succession which will put royal daughters on the same footing as sons.
Those in line for the throne will also be allowed to marry Roman Catholics for the first time in 300 years without giving up their claim.
The 85-year-old Queen's visit has been billed by some commentators as her last, in light of her age. But Buckingham Palace has dismissed speculation that it was a farewell tour.
A Royal official said: "The Queen and Duke have really enjoyed themselves. The Queen has been bowled over by the reaction."
The 90-year-old Duke, who looked smart in a dark two-piece suit, stopped at a stand manned by chef Vincent Garreffa and was persuaded to get involved.
Mr Garreffa said: "We had a ribeye steak and a pork cutlet which were waiting to be turned, and he did us proud."
But Prince Philip could not be cajoled into sampling the cook's array of barbecued prawns, crayfish and scallops.
"I can't tempt you with a little seafood?" Mr Garreffa asked, but the Duke shook his head, saying: "I'm not in the mood."
As the Prince left he was presented with a book of barbecue recipes by Lyn Barnett, wife of Western Australia Premier Colin Barnett.
Up to 200,000 people were expected at the event, staged on the foreshore of Perth's Swan River, which was attempting to beat the world record for the largest barbecue.
To feed the crowds, the organisers laid on 130,000 sausages, 8,000 loaves of bread, 60,000 litres of sauce and 150,000 drinks.
The main purpose of the Australia tour was to allow the Queen to open the Commonwealth Heads of Government Meeting in Perth, and last night, after presiding over the launch ceremony, she hosted a lavish banquet in honour of the world leaders.
The Queen's visit ended with a low-key farewell on the Tarmac at Perth International Airport.
A few hundred well-wishers gathered behind a wire mesh fence to watch the goodbyes, and as the Queen's motorcade arrived, Governor General Quentin Bryce and her husband, Michael, stepped forward and greeted the Royal couple as they emerged from their Range Rover.
The two women chatted for a few minutes before the head of state was introduced to federal and state representatives.
The Queen and Prince Philip then climbed the plane's steps and, at the top, the blustery conditions forced the Queen to hang on to the brim of her hat for a few seconds before the pair waved goodbye.
They are due to arrive back in the UK in the early hours of Sunday morning.
