The UK's famous seed bank - opened by King Charles in 2000 and managed by Royal Botanic Gardens - serves a vital role in preserving nature, and strives to protect plant species from being lost to climate change and environmental threats.
In the 22-minute podcast episode - which was recorded at Windsor in July - Blanchett, 56, said: "There is an urgency to the work that the seed bank does.
"I was shocked to learn that 97 per cent of the wildflower meadows have been decimated.
"I don't think it's something that we quite understand here, because we look around us and in the immediate term, we see so much natural beauty.
"But we don't think how fragile it is."
King Charles said the work of the Millennium Seed Bank is vital in preserving biodiversity for many generations to come.
The King added that he is "very proud" to be a patron of Kew: "I think it's wonderful what the seed bank is doing, but we've got to speed up the process."
As well as the Millennium Seed Bank, Blanchett and the King discussed how the pharmaceutical industry plays a role in protecting plant life, as many medicines come from plants.
It's not King Charles' first podcast, as back in March, he created a playlist for Apple Music called The King's Music Room, in honour of Commonwealth Day. Among his choices were Kylie Minogue's The Loco-Motion and Crazy in Love by Beyonce.
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