Get up to 40% off on sale items in our Calvin Klein collection. Calvin Klein is the legendary American fashion house known for its signature clothing and underwear lines. Originally founded in 1968, Calvin Klein has grown to become one of the most recognisable designer labels with a strong following amongst fashion fans the world over. The boys and girls Calvin Klein underwear collection has just arrived at Base for the Autumn/Winter season with a stunning selection of underwear, nightwear and basics for children from 4-16 years. Browse the collection today and add a touch of designer style to your wardrobe with Calvin Klein kids.