Struggling to survive as a child on the streets of a Ugandan slum, Phiona Mutesi probably didn't expect her life story to be turned into a Disney film.

Living in the impoverished township of Katwe in Kampala, she had tragically lost her father and one sibling - and her family regularly went without food.

But her luck all changed when she discovered chess.

Phiona was introduced to the game when she went to a local chess club because they provided free food for participants, and her coach soon realised she had natural talent.

She would soon become a Ugandan chess champion, travelling the world competing in tournaments and managing to build her mother a house out of the slums with the prize money she earned.

Her story got the attention of Disney, who decided to turn it into a film.

Last night, Oscar winner Lupita Nyong'o joined British star David Oyelowo for the premiere of the Queen Of Katwe in Leicester Square.

Nyong'o, who scored an Academy Award for her role in 12 Years A Slave, plays the mother of 10-year-old Phiona in the film, which was shot in Uganda and South Africa.

Raised in Kenya, she emphasised how important it was to her to tell positive stories about Africa.

"The fact it was an African story, one that was positive and heartwarming, we don't get many of those given this platform," she said.

"I think it's in telling specific stories that you open the world to the universality that exists everywhere in the world and I think Mira Nair did that with this film.

"She doesn't shy away from the specifics of Uganda or Katwe and in doing that, captures something we can't deny is true of humanity and I think that is what people are really responding to.

"We have that human understanding of what it means to be an African and being an African is a very diverse thing in itself, so this is just one of many stories yet to be told."

Oyelowo, of African descent himself, added: "I've felt that there haven't been enough of these kind of stories, we've seen a lot of the negative side of life in terms of Africa but this is a life-affirming story, this is universal in its theme of a young girl with a dream and achieving it, and so I wanted to see that in the world.

"The fact that a young girl in London can see the story of a young girl from a slum called Katwe and relate to it, I hadn't seen that before."

Queen of Katwe is released in UK cinemas on October 21.