Stars of the film Queen of Katwe have paid tribute to actress Nikita Pearl Waligwa who has died at the age of 15.
Waligwa had been diagnosed with a brain tumour and died in hospital in Kampala on Saturday.
She starred in the 2016 Disney film which was based on the true story of Phiona Mutesi, a chess prodigy from a Ugandan slum.
Her co-star David Oyelowo wrote on Instagram: "She was a ball of light in Queen of Katwa and in life."
He played the role of Phiona Mutesi's chess teacher while Lupita Nyong'o played her mother.
Waligwa featured as the character Gloria, a friend of Phiona who explained the rules of chess to her.
Ms Nyong'o said on Instagram: "She played Gloria with such vibrancy. In her real life she had the enormous challenge of battling brain cancer."
Gloria Nansubuga, the 19-year-old Ugandan chess star who was played by Waligwa, told the BBC: "I couldn't bear to hear that someone who acted as me in a film had died. I loved her from my heart.
"She told me she wanted to learn how to play chess. I wanted to have lessons with her but she was always in hospital. She was so caring even though she was so young."
Waligwa was first diagnosed with a brain tumour in 2016 and Queen of Katwe director Mira Nair reportedly mobilised people to help fund her treatment in India, with Ugandan doctors quoted as saying they did not have the necessary equipment.
In Uganda, only a fraction of patients with such serious conditions get the medical help they need due to costs.
She was given the all-clear in 2017 and went back to secondary school. However, last year, she was found to have another tumour.
Her death was announced by her school on Twitter.
"You were a darling to many and we have lost you to a brain tumour at such a tender age," Gayaza High School said.
The funeral service for Waligwa was held on Sunday, and she is being buried on Monday.
By Catherine Byaruhanga, BBC News, Kampala
In the middle of the day on the outskirts of Kampala, hundreds of mourners huddled under tarpaulin tents and trees for Waligwa's burial.
From the speeches given, especially by Waligwa's mother and father, the toll of her long battle against cancer comes to light.
Three recurring tumours and almost as many surgeries left her young body weaker and more fragile.
Her mother, Rachel Asiimwe Waligwa, talked of her daughter's pain but also the grace with which she managed to carry on through difficult times.
The cost of Nikita's treatment from her first diagnosis in 2016 was supported by the Disney company which produced Queen of Katwe, relatives, family friends and her parents' colleagues. Many of them attended the funeral.
Her story resonates because a beautiful talented girl who achieved success at a young age, died much sooner than she should have.