Prince William protected Kate Middleton from the elements at the African Cats premiere

Prince William used an umbrella to protect Kate Middleton's grey Matthew Williamson dress from torrential rain as they arrived at the premiere of African Cats at BFI Southbank last night.

Kate, 30, paired her detailed peplum-style dress with a black clutch bag and court shoes to watch the documentary, which tells the story of the big cats' struggle for survival in Kenya's Masai Mara.

A portion of the proceeds from the film will go towards animal conservation charity Tusk Trust, of which William, 29, is patron.

The story will have resonated with the couple - who celebrate their first wedding anniversary on Sunday - as they became engaged in Africa.

After the showing, William gave an impassioned speech.

'Wow, that was amazing. I'm emotionally exhausted. There's more drama in that than EastEnders,' he said.

'African Cats shows the battle for survival facing every lion and cheetah born in the wild.

'Tomorrow will be too late. Loss of natural habitat, due to encroachment by human beings, is the principal reason that there are today around just 25,000 lions remaining in the African bush - 50% less than 2 years ago.'

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Anna Duff