Rihanna is seeking a donor for an Olympic hopeful battling leukaemia.

The 'Russian Roulette' singer – who received a touching letter from 26-year-old Seun Adebiyi, a Nigerian athlete who had hoped to compete in the 2014 Winter Games in skeleton sledding, but was diagnosed with Leukaemia during training – has promised to do everything she can to raise awareness of his condition and find him a bone marrow donor.

Rihanna said: "Leukaemia interrupted Seun's dream of being the first Nigeri...