McLachlan, Tegan and Sara and more than 200 performers will take part in a brief opening ceremony at Commonwealth Stadium before the tournament opener between Canada and China.
As befitting the competition, the opening ceremony tells the story of a little girl who plays soccer.
"It's really thrilling," McLachlan said of being part of it. "I'm a proud Canadian, I'm glad it's being hosted here. And I'm a soccer mom as well so my little girl's going to be watching.
"I think the game of soccer is an amazing sport. It's great for women, in particular young girls, being part of something bigger than themselves. And (I'm) just super-proud to be here."
McLachlan, 47, has two daughters. Her youngest, eight-year-old Taja, plays soccer.
McLachlan plans to perform "In Your Shoes," a song inspired by Malala Yousafzai, the youngest-ever Nobel Prize laureate. Yousafzai, who campaigned for education and wrote an anonymous diary about life under Taliban rule in Pakistan, survived being shot by militants.
"It's definitely about inspiring young girls to pursue their dreams and not be knocked down. Well they might get knocked down but they're going to get right back up again and do it no matter what," McLachlan said Friday before rehearsal at the stadium.
The singer said she has seen progress in women's empowerment but cautioned against complacency.
"We have to continue to stand up and speak out for equality. But definitely shifts are slowing occurring and the Women's World Cup is a big part of that, for sure."
While a crowd of 52,000 is expected Saturday, McLachlan does not expect to have any nerves.
"It's fun. This is what I do," said McLachlan, who has performed in front of 75,000 at Quebec's Festival d'ete. "I love singing, so it's easy for me."
Saturday's World Cup kickoff show also features Tegan and Sara, originally from Alberta.
"Honoured to support these world class athletes!" the identical twins tweeted.
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