A Canadian star is adding her voice to a chorus of advocacy and labour groups in denouncing the controversial Trans-Pacific Partnership deal, teaming up with punk rockers and hip hop artists in an effort to reach an audience that might not otherwise care about international trade.

Actress Evangeline Lilly, best known for her role in the hit TV series "Lost," will be speaking at the Rock Against the TPP show in Toronto on Friday, the touring event's only Canadian stop.

Lilly, who is Canadian but lives in the U.S., called the TPP a "backdoor way for multinationals to squeeze things into law" without the usual public scrutiny.

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The Alberta-born actress said the deal affects everything, from fair wages and labour rights to Internet freedom and health-care costs.

She echoed some of the more common criticism levelled at the TPP — such as the risk of large corporations suing governments over legislation that indirectly curtails their profits — in calling for residents on both sides of the border to rally against the deal.

While international trade agreements aren't on most people's radar, Lilly said she hopes Friday's event — which includes the punk band Anti-Flag — will capture the public's attention.

"If the average Canadian knew what the TPP was and knew that it was in the process of needing to be ratified by Parliament... they would be up in arms about it," she said in an interview.

The TPP is the most significant regional trade agreement that Canada has negotiated since NAFTA, which concluded nearly two decades ago. The wide-ranging accord covers 40 per cent of the world economy and, if ratified, would set new international rules for sectors beyond trade.

Last week, a government study projected that Canada would generate more than $4 billion in long-term GDP gains if it ratified the agreement, but stands to take a $5-billion-plus hit to its economy if it opts out.

But the analysis, conducted by the Office of the Chief Economist at Global Affairs Canada, only considered the impact if Canada is the lone holdout. It did not look at what would happen if the deal falls through in its entirety.

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Supporters have said the TPP would open foreign markets and could bolster some sectors, such as forestry and agriculture.

Critics, including some law experts, business leaders and economists, have raised the alarm about possible repercussions for intellectual property, manufacturing jobs and workers' rights.

Economist Joseph Stiglitz said the deal benefits big business at the expense of working people, driving down the bargaining power of workers, including their wages.

Ottawa has said it is keeping an open mind about the deal and is following through on its promise to consult widely with Canadians. The House of Commons trade committee is currently studying the TPP.

After that,International Trade Minister Chrystia Freeland has promised that only a vote in Parliament would ratify the deal, which was negotiated under the former Conservative government.

In the U.S., both Democrat and Republican U.S. presidential hopefuls have come out in opposition to the TPP, though President Barack Obama has previously spoken strongly about the need for countries to swiftly ratify the deal.

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Lilly said now is a "pivotal time" for Canadians to show their government how they feel about the agreement.

"Now is a very good time for (the Trudeau government) to hear that there is a massive rally going on in Toronto that's opposing the TPP," she said.

"What will be useful for the road show right now is to send a very clear message to Trudeau and to his government that should you decide to ratify the Trans-Pacific Partnership, there is political cost in that."