The most highly-anticipated event of the Alberta election campaign unfolds tonight as the leaders of the province's four largest political parties face each other in a televised debate.

Progressive Conservative Leader Alison Redford, NDP Leader Brian Mason, Liberal Leader Raj Sherman and Wildrose Leader Danielle Smith will debate each other for 1½ hours starting at 6:30 p.m. MT.

Many observers are particularly eager to see Redford and Smith go head to head.

The two women are locked in a race that has attracted national attention because the Tories' 41-year dynasty could fall to the surging Wildrose Party in the April 23 election.

Polls suggest the parties are running neck and neck, with the Wildrose attracting more support in Calgary and southern Alberta.

With the race so close, the debate takes on huge importance, according to Calgary pollster Bruce Cameron.

"When there's a really good performance or a really poor performance, the results can be very dramatic," he said. "They affect people's perception of the leader, they affect the image of the party, most importantly, they affect the momentum."

Smith is seeking her first seat in this election and says she has spent time preparing for this debate.

"This is the first time that I've done this," she told reporters in Calgary on Wednesday.

"They all have a lot more experience than I do. They've all been in the legislature. They all know each other's styles so I feel like I'm a bit of an underdog going into this race. So I'm not taking anything for granted."

As for Redford, the debate gives her a chance to regain some of the ground her party has lost to the Wildrose.

"What Albertans are going to be looking for is to test whether or not that person on that screen on Thursday night really has the decorum, the background, the perspective and the experience to be the premier of this wonderful province," Redford said Tuesday on CBC's Power & Politics.

Mason, Sherman also hoping to make an impression

The stakes are also high for Sherman and Mason.

Sherman, a former Tory who became Liberal leader in September, is trying to rebuild his party, which lost seats in the 2008 election and underwent a fractious leadership race last year.

An emergency room physician who entered politics four years ago, Sherman admits he faces a challenge from his rivals Thursday night.

"I'm ready to debate the other three candidates. They are professional debaters, I recognize," he said.

"I have a lot to say, want to fight for Albertans, so I'll do the best that I can."

Mason will be by far the most experienced leader in Thursday's debate.

First elected leader in 2004, Mason is taking the provincial NDP into its third election with him at the helm.

Mason made headlines on March 30 when he sent a letter to his opponents decrying the negative and aggressive tone of campaign. He said on Wednesday that he wants to put his own ideas forward during the debate.

"I think some players are going to be playing defence. Some people are going to be playing offence," he said when asked to sum up the debate using a hockey analogy.

"I just want to play a winning game."

CBC will carry the debate live on the Calgary, Edmonton and Alberta Votes 2012 websites and on CBC Radio One in Alberta.

The debate will be replayed on CBC Television from 8:30 p.m. to 10 p.m. If the hockey game ends after 8:30 p.m., CBC will join the broadcast in progress.

CBC is also hosting a live chat with Alberta @ Noon host Donna McElligott and CBC Reporter Scott Dippel, who will provide analysis and answer questions while the debate is underway.