Sure, Trudeau's inclusion in the ad was subtle, but in a pricey 30-second spot, every image counts.
The clip caught the attention of QMI Agency's David Akin, who called the federal leader's appearance in the commercial "unusual," but also suggested it may help increase McNeil's popularity.
"While federal NDP Leader Thomas Mulcair, for example, campaigned with BC NDP Leader Adrian Dix in the recent B.C. provincial election, I'm not aware of any advertising in which Mulcair appeared with Dix," Akin wrote on his blog. "Anyone else know of political advertising by a provincial party featuring a famous, popular and good-looking federal leader of the same party?"
A quick look through McNeil's Facebook page reveals three albums featuring photos of both the N.S. Liberal leader and Trudeau, who participated in a fundraiser in October, 2012 and rallies in both the spring and summer in support of Nova Scotia Grits.
At a rally in May, Trudeau vowed to do everything he could to help McNeil defeat Dexter, calling the provincial election a top priority, The Chronicle Herald reported.
"The best way to help the Liberal Party of Canada is to elect a Liberal premier in Nova Scotia," Trudeau told supporters.
The federal Liberal leader also promised to make more visits to help McNeil’s campaign.
"One of the great things about our party in Nova Scotia is that we work very closely together with the federal party, and we’ll be relying on them," McNeil said. "We’ll be relying on Justin."
Just a few months earlier, McNeil endorsed Trudeau in the federal Liberal leadership campaign.
"Justin brings passion and energy to federal politics that is catching people's attention," McNeil said. "People have been captivated by his campaign because he is focused on moving our country and our party forward."
Interestingly, McNeil broke from Trudeau this summer on the issue of marijuana legalization, saying he backs decriminalization instead.
But Mulcair's experience in British Columbia illustrates the hazards involved when a federal leader puts some skin in the provincial game.
The federal NDP leader wasn't shy about his desire to see the provincial New Democrats win the B.C. election and even campaigned with Dix's team.
"I have three priorities for the spring session," Mulcair told HuffPost Canada in April. "The first is to get Adrian Dix and the NDP elected in B.C., the second is to get Adrian Dix and the NDP elected in B.C., and the third is to get Adrian Dix and his party elected in B.C."
Unlike other political parties in Canada, NDP federal and provincial branches are very integrated. As such, some pundits viewed Dix's loss as something of a low point for Mulcair as well.
The Toronto Star's Chantal Hebert said Mulcair needed British Columbians to "lead by example by handing the reins of their province to the NDP."
National Post columnist Kelly McParland said the loss effectively put Muclair on notice to abandon his "anti-energy rhetoric" or suffer the same fate as Dix.
"Thomas Mulcair should be one worried Leader of the Opposition when he awakes today," McParland wrote the day after the vote.
With McNeil now the acknowledged front-runner in a campaign that is expected by many to get nasty, is it possible a loss in Nova Scotia could reflect poorly on Trudeau? Tell us your thoughts in the comments below.
Related on HuffPost:
Federal Liberal Leader Justin Trudeau and Nova Scotia Liberal Leader Stephen McNeil, right, arrive at the Public Gardens to meet with supporters in Halifax on Friday, Aug. 30, 2013. THE CANADIAN PRESS/Andrew Vaughan
On May 24, 2013 Nova Scotia Liberal Leader Stephen McNeil was joined by Liberal Party of Canada Leader Justin Trudeau for a day in Halifax and a rally at Pier 21
UP NEXT: Memorable Trudeau Photos
Come At Me, Bro
Justin Trudeau trains at Pan Am Boxing Club in Winnipeg on Friday Feb. 1, 2013.
Justin Trudeau & co. making faces.
Justin Trudeau splits his pants while pushing the "scrum machine" in support of Prostate Cancer Canada in Toronto Thursday, July 21, 2011.
Justin Trudeau gets his geek on at Montreal Comiccon in September 2012.
So Long 'Stache
Justin Trudeau has his moustache shaved off to raise money for the Judy LaMarsh Fund, that supports female candidates, at the Liberal Party convention in Ottawa on Saturday, January 14, 2012.
Coming For MacKay
Minister of National Defence Peter MacKay (left) is chased by Liberal MP Justin Trudeau in a motorized wheelchair during a wheelchair race relay on Parliament Hill in Ottawa on Wednesday, May 12, 2010. Twenty-five MPs and senators used a wheelchair for the day in support of the Canadian Paraplegic Association's Spinal Cord Injury and CPA awareness month.
All For One, One For All
Justin Trudeau all dressed up for the Montreal Movember Gala in 2010.
Pierre Trudeau's sons, Sacha, left, and Justin, tackle their mother's paperboy in Ottawa in this undated photo.
'Family... And A Cow.'
He Can Certainly Take A Punch
Alexandre (Sacha) Trudeau delivers a right hook to his older brother Justin during a play fight in 1980 at Ottawa airport as the boys await a flight with the return of their father, then-prime minister, Pierre Trudeau.
Be Honest With Me, Who's Cuter?
Justin Trudeau strikes a pose with an adorable baby.
A Very Furry Christmas
Justin Trudeau poses with his family on his 2010 Christmas card.
Former Liberal MP Ken Dryden, left, and Justin Trudeau play table hockey as they visit Sun Youth, a community organization, Monday, Jan. 14, 2008 in Montreal.
Yanking Their Chain
Then-prime minister Pierre Trudeau, left, watches as his 11-year-old son Justin swings on a chain during a tour of an old fort in the Omani town of Nizwa Dec. 2, 1983. Trudeau and Justin spent the day visiting the towns of Jebel and Nizwa 165 kilometres south of Muscat.
Justin Trudeau in Muskoka, Ont.
Liberal MP Justin Trudeau, centre, has his cowbay taken by his son Xavier, 4 years-old, while his wife Sophie Gregoire, second from left, holds daughet Ella-Grace, 3 years-old, while they attend the party's annual Stampede breakfast in Calgary, Saturday, July 7, 2012. This is the 100th anniversary of the Stampede.
Like Mother, Like Son
Eleven-month-old Justin Trudeau, urged on by his mother Margaret Trudeau, crawls up the steps of an aircraft in Ottawa on Dec. 5, 1972 to meet his father, then-prime minister, Pierre Trudeau on his return from Britain.
Cutting A Rug
Justin Trudeau dances with wife Sophie Grégoire before his speech at the Liberal showcase on April 6, 2013.
Next: What Is Pierre Trudeau Doing?
Prime Minister Pierre Trudeau, wearing what someone called his "Mandrake the Magician outfit," walks down the grandstand steps to present the Grey Cup trophy to the victorious Montreal Alouettes in this Nov. 28, 1970 photo.
Hey, It Was The '70s
Pierre Trudeau leans over to kiss an unidentified young lady to the seeming surprise of his recent bride Margaret. Trudeau and Margaret spent Saturday March 27, 1971 at maple tree farm here near Montreal at a sugaring out party.
Fur Wasn't Always Controversial
Pierre Trudeau accompanies Margaret Sinclair, at the annual Governor General's skating party for members of Parliament in Ottawa Jan. 14, 1970.
Ditto For Seal Hunting
Pierre Trudeau looks through the scope of his rifle while on a seal hunting trip in Baffin Island's Clear Water Fjord, July 29, 1968.
A Leg Up
Pierre Trudeau shoes off his frisbee catching style while waiting to board his plane in Vancouver May 16, 1979.
Calisthenics Were Still Cool
Pierre Trudeau had no trouble keeping himself occupied during a break from a boat trip down the Northwest Territories, Nahanni River, Monday Aug. 4, 1970.
Pierre Trudeau takes a wary look at an ice crevice, decides to chance it and makes the leap successfully during a midnight seal- hunting expedition at Clearwater Fjord in Canada's Arctic, July 29, 1968.
When in France...
Pierre Trudeau receives a kiss from his wife Margaret during a tour of St. Pierre, France, Aug. 1971.
Pierre Trudeau in Guayana 1974.