The competition had been billed as the battle of the North American couples and the Olympic champions trumped American rivals and 2011 world gold medallists Meryl Davis and Charlie White with a unique interpretation of the musical Funny Face.
Davis and White captured the public's imagination with their performance to Strauss's Die Fledermaus overture but the final score showed they had been blown away by the Canadians' total of 182.65. Davis and White compiled 178.62.
France's Nathalie Pechalat turned up in Nice with a broken nose but that did not stop her producing a stunning performance with Fabian Bourzat as they picked up their first world medal, a bronze with 173.18.
The Canadians seemed rather underwhelmed with their outing and felt they had bluffed their way to gold with an Oscar-winning acting performance rather than their skating skills.
"We really wanted to embody (the spirit) of Fred and Audrey... it wasn't even our best skate today but it's nice that we get the opportunity to get into character and have some fun expressing ourselves," Virtue told the crowd after winning back the title they claimed for the first time in 2010.
Moir, with his dark hair gelled back, added: "We had to fight for the programme rather than it being the fairytale skate we had been hoping for. At the one minute mark I had a little stumble but luckily my character at that point is shocked and surprised so I just kind of played it off as part of the choreography."
The victory ended a difficult 18 months for the Canadians as their 2010-2011 season was limited to a handful of competitive appearances after Virtue had surgery on her shins.
Davis and White won a standing ovation for their four-minute exhibition, which featured crowd-pleasing lifts and fast-paced twizzles as it built towards a rousing finale.
Pechalat and Bourzat were cheered on to the ice and then brought the house down as the final strains of their Pharoh and His Mummy music got lost in the deafening roars that shook Nice's Acropolis arena.
In between the duo imaginatively weaved in moves that were beat-perfect to the music and did not seem to hold anything back despite Pechalat's nose being out of joint.
Bourzat hoisted his upside-down partner on his shoulders and also performed a cantilever lift, winning stamps of approval from the crowd.
When it came to the top prize, though, White and Davis were ultimately disappointed by the judges.
"We feel like we skated our hearts out," said White. "We don't know where the discrepancy was in the judges' eyes. We were aiming for first so are disappointed we didn't get that."
While the favourites ruled the roost in the ice dance, the expected front runners in the women's event slipped and stumbled.
Kitted out as a pirate complete with knee-high, brown boots, Russian Alena Leonova slayed the favourites to grab the surprise lead in the women's short programme.
In the absence of Japan's Miki Ando and South Korea's Kim Yuna, the top two from 2011, established skaters such as twice former champion Mao Asada, four-times European gold medallist Carolina Kostner and Four Continents winner Ashley Wagner of the United States had been tipped to fight it out for the medals.
Leonova, however, hijacked the competition with her swashbuckling performance to the Pirates of the Caribbean soundtrack, nailing all her elements, including a soaring triple toeloop-triple toeloop combination, to earn a personal best score of 64.61.
She ended the two minute-50 second exhibition with a menacing glare and a throat slitting gesture with her gloved hand, no doubt striking fear into her rivals.
"It was my best performance of the season and probably of my life," said a breathless Leonova who is well placed to get 2014 Winter Olympic hosts Russia back on the women's podium for the first time since 2005.
Japanese teenager Kanako Murakami trailed by 1.94 points while Italy's Kostner stood third with 61.00 after doubling a scheduled triple loop.
Japan's Asada was the only woman of the 30 competitors to attempt the triple Axel but her gamble backfired as she fell to the ice and finished fourth with 59.49.