The United Nations refugee agency said it had appointed Blanchett as its newest Goodwill Ambassador, a role long famously held by US film star Angelina Jolie.
"I am deeply proud to take on this role," Blanchett said in a statement, stressing that "there has never been a more crucial time to stand with refugees and show solidarity."
"We are living through an unprecedented crisis, and there must be shared responsibility worldwide," she added.
But solidarity has recently appeared to be in short supply in Europe for instance, which is facing surging xenophobia as it reels from its worst migration crisis since World War II.
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"It feels like we're at a fork in the road, do we go down the compassionate path or do we go down the path of intolerance?" Blanchett said.
"As a mother, I want my children to go down the compassionate path," she added.