In celebration of Canada's 150th birthday, the Scotiabank Calgary Marathon has added a 150-kilometre race to its 2017 event.

And people are actually signing up.

In fact, 65 runners from across Canada and the U.S. have already registered for the ultramarathon.

Not too shabby for an event that was pitched as a pie-in-the-sky idea.

"It did come off as a bit of a lark," said Kirsten Fleming, executive director of the Calgary Marathon Society.

"But the president of the board was like, 'Yep, we're doing that, that's awesome.'"

Fleming said it's going to be a "really unique, one-time event" for both participants and spectators.

"Ultramarathoning is really a niche and very kind of hidden away type of race and we're really doing something special by bringing it into the mainstream."

Organizers are expecting 15,000 people to take part in the 2017 Scotiabank Calgary Marathon. (Scotiabank/Marketwire)

Running through the night

Participants in the 150-kilometre race will start the night before the Calgary Marathon.

Runners will tackle the first 100 kilometres on a controlled, 10-kilometre loop along the Bow River pathway between Edmonton Trail and the Crowchild Trail underpass.

Fleming said there will be cheering squads and food stations along the route to keep the runners motivated and fueled up.

"I don't know if you can taste anything at three in the morning after you've been running 50 kilometres, but there's going to be pizza and Spolumbo sausage and all sorts of goodies," she said.

"We're working with a number of really experienced ultrarunners just to provide some insight on what people might want at certain times of the night."

Once the ultramarathoners complete that 10-kilometre loop — ten times over — they will join about 15,000 other Calgary Marathoners for a 7 a.m. forced start along the regular route.

Except, instead of running the standard 42.195-kilometre marathon, they'll be running 50 kilometres.

Individual participants have 18 hours to complete 150 kilometres. There is also a relay event where anywhere from two to 11 runners can team up.

Staring in February, Calgary ultramarathoner Dave Proctor will be leading monthly training sessions for locals planning to tackle the 150 km race at the Calgary Marathon this spring. (Neil Zeller Photography)

Dave Proctor to lead ultramaraton training

Locals who have signed up for the 150-kilometre race have a chance to be mentored by a super ultramarathoner.

Dave Proctor, who set a Guinness World Records on a treadmill this year by running 260.4 kilometres over 24 hours, will be leading monthly training sessions along the course route starting in February.

"They'll do 40 kilometres out on the course at night so they can … get a feel for what the event is going to be like," said Fleming.

"And we hope that that means that at the start line, at least for the people in Calgary and area, there will be this sense of community."

With files from the Calgary Eyeopener