An underwear t-shirt has many different uses. It can be added to your nightwear, used as a layering piece, worn to the gym or simply thrown on as an alternative to a thicker standard t-shirt. Discover the underwear t-shirt range from Calvin Klein at Zee & Co. Composed using high quality fabrics, each long and short sleeve garment provides a comfortable and flattering fit, complete with plain styles in a variety of colours or subtle branded designs. In both slim and regular fits and with new designs added each season, there's plenty to choose from!