The present invention describes a hair treatment application system, comprising at least one or more hair treatment compositions (15) having a viscosity of from 3,000 cPs to 150,000 cPs and a hair treatment application device (1) comprising a first plate (10) and a second plate (20) positionable in a juxtaposed relationship when said hair treatment application device (1) is in a closed state. The hair treatment application device (1) is characterized by having a first zone comprising at least one absorbent substrate (40) on the internal surface (101) of said at least said first plates (10) and a second zone (50) on said internal surface (101) which is free of said absorbent substrate (40). Said at least one absorbent substrate (40) has a median pore radius of from 300 microns to 3,000 micron. The present invention describes also methods of treating the hair with said hair treatment application system (10) and kit comprising said hair treatment application system.