Stella McCartney is now the proud mum of two boys and two girls! The famed designer and husband Alasdhair Willis welcomed their daughter Reiley to the world on Tuesday in London. The lil darling is the couple's fourth child in five and a half years. She joins brothers, Miller, 5, and Beckett, 2, and sister, Bailey, nearly 4. We imagine their grandpa, former Beatles singer Paul McCartney, is overjoyed with his family's newest addition. In light of Stella's children's line, we are sure this infant will be dressed to the nines.