The last time a Canadian prime minister named Trudeau was at the White House for a state dinner was in 1977. He dined on Alaska king crab and his wife's outfit caused a stir.

On Thursday, Prime Minister Justin Trudeau and his wife, Sophie Grégoire-Trudeau, will be feted in Washington — and her fashion statement will almost certainly come under scrutiny as well.

After all, this will be a glitzy and glamorous evening, courtesy of President Barack Obama and his wife, Michelle, who extended the invite for an official state visit to the Trudeaus last year.

Now, after months of planning, the finishing touches are underway.

It's been a while since the White House hosted a prime minister from north of the border. In fact, it was 19 years ago when Jean and Aline Chrétien were the guests of the Bill and Hillary Clinton.

Ann Stock helped plan that dinner, and many others during her tenure as White House social secretary in the 1990s, a job she described as exciting and rewarding.

State visits are a big deal, she says. "This is probably the highest honour the United States can give a country, and every single country, no matter which one, wants a state visit," said Stock.

Very coveted invite

Trudeau's visit will include an official welcoming ceremony on the South Lawn of the White House ("We always pray for no snow and no rain," says Stock). Meetings between the leaders and other officials will follow, where a climate change strategy, trade and border security are all expected to be on the agenda.

Pierre Trudeau, left, visited Washington several times, including a visit with President Ronald Reagan in 1983. Trudeau was honoured with two state dinners during his years as prime minister. (Scott Stewart/Associated Press) There will also be a working lunch and news conference, and then, at night, the real fun begins.

"This will be a very, very coveted invitation," said Stock. "It's an invitation that no one turns down."

The White House is keeping the guest list under wraps, but Stock said when officials plan these dinners they think carefully about who is included. They try to pick a diverse crowd and choose invitees they think the prime minister would enjoy meeting.

Justin Trudeau will be only the sixth Canadian prime minister to receive an official state dinner in Washington. Here's a look back at the other state visits. 2:26

It's not a long list, though; the dining room only holds about 130 people.

A lot of thought is also put into the menu, décor and live entertainment.

"You're thinking of this as a welcoming invitation from the United States. You're really trying to showcase the best of America — American food, American entertainment, American wine, American style," said Stock.

The teams who plan these lavish events do their research. They make sure the guests of honour have no dietary restrictions, for example, and aren't allergic to certain flowers.

"You want to get it exactly right, because if you don't, you know it's going to be a story."

Trudeau took a dip at the White House

Brian Mulroney was twice honoured with state visits, courtesy of then president Ronald Reagan in 1986 and 1988.

The two leaders, who were known to bond over their common Irish heritage, talked about tackling the effects of acid rain, developing a joint manned space station and other issues while they dined on veal, smoked salmon and pasta with seafood.

President Bill Clinton and his wife, Hillary, centre, hosted Canadian Prime Minister Jean Chrétien and his wife, Aline, for a state dinner in 1997. That was the last time a Canadian leader was given the honour. (Reuters) When they gave the toasts, they stuck to the tradition of gentle jabs and witty jokes, according to the White House Historical Association account.

When Pierre Trudeau visited in 1977, he and then president Jimmy Carter discussed oil and natural gas exports, and the prospect of Quebec separation. René Lévesque's Parti Québécois had just been elected the previous fall.

On that night, Margaret Trudeau's short dress raised eyebrows and was widely criticized by American designers, but she didn't pay it any mind. "Look, I just don't care what the American designers thought. What I wear is nobody's business but my own," she said.

Her daughter-in-law has already been the subject of fashion stories, positive ones mostly, and the photogenic former TV host will surely generate attention for whatever she chooses to wear on Thursday.

Guests awed by experience

On Pierre Trudeau's first state visit to the White House in 1969, Americans were eager to see the man who had inspired "Trudeaumania."

President Richard Nixon threw a dinner for 121 guests who were entertained by singer Robert Goulet. Trudeau talked about his passion for skiing and deep-water diving, and, later, his request to take a dip in the White House pool was granted.

A table setting for the state dinner with U.S. President Barack Obama and British Prime Minister David Cameron in 2012. A dinner will be held in honour of Canadian Prime Minister Justin Trudeau on March 10, 2016. (Joshua Roberts/Reuters) When Justin Trudeau and the lucky guests on Thursday walk into the White House, they should prepare to be amazed, according to Stock.

She said she loved watching people realize that they are standing in the president's home, not just the current president, but the ones before him.

The White House is not only a centre of power, she said, but it's also a residence and a museum full of American treasures and artwork.

"People get a living, walking history lesson as they are in the White House," she said. "This awe goes over people. It is one of the most exciting evenings you can ever attend."