An actress who starred in the Queen of Katwe, a Disney film about a chess prodigy from a Ugandan slum, has died aged 15, Ugandan media report.Nikita Pearl Waligwa had been diagnosed with a brain tumour.The 2016 film was based on the true story of Phiona Mutesi, who took up chess aged nine despite not being in school and went on to compete in international tournaments.It starred Lupita Nyong'o as her mother and David Oyelowo as her chess teacher.Waligwa played the role of Gloria, a friend of Phiona who explained the rules of chess to her.She 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.She was given the all-clear in 2017 but last year was found to have another tumour.