Model Jourdan Dunn has launched her first campaign for the Sickle Cell Disease Association of America, for which she's a Parent Ambassador, after her four year old son Riley was diagnosed with the disease.

The campaign, Cell For Gratitude, sees Dunn designing a necklace which represents a cell, with all proceeds going to the charity. Dunn told Vogue 'When the Sickle Cell Disease Association approached my agency and said, "We'd really like to have Jourdan as the ambassador", I was immediately excited to spread more awareness of the disease and help raise funds, and do whatever I can to help out. It is a cause that is truly close to my heart'.