"I don't think this picture went viral enough," she wrote.
Her post has already been retweeted more than 600 times.
And while it's unclear what exactly struck Mulcair's funny bone last week, we at HuffPost Canada Politics may have a guess.
On Thursday, Harper said repeatedly that "very few people" knew about Duffy's deal with Wright. Previously, the prime minister had said nobody knew about the scheme.
But did Harper's changed tune lead to laughter?
There was a moment that seems to match what's going on in this shot — Harper speaking and emphatically pointing his finger, while someone else is heard laughing.
Watch the video below for yourself.
Mulcair had asked the prime minister if Wright, his current chief of staff Ray Novak or Conservative Senator Carolyn Stewart Olsen threatened to expel Duffy if he didn't accept the $90,000 deal.
"Again, Mr. Speaker, he alleges that many people knew about this. That is simply not correct," Harper said. "It was Mr. Wright's decision, using his own resources and by his own admission, documented, he told very few people.
"The fact of the matter is that it is the virtually universal view in this party that if a person cannot follow rules, cannot respect the standards of integrity in their behaviour, people do not want them to be a member of the caucus of the Conservative Party."
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Justin Trudeau & co. making faces.
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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
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All For One, One For All
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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.
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