The present invention is related to a process for colouring and permanent shaping keratin fibres especially human hair in a single process. The novel process for colouring and permanently shaping keratin fibres especially human hair according to the present invention includes the following steps:a- an aqueous oxidative colouring composition based on at least one oxidative dye precursor and optionally at least one coupling substance but not comprising any direct dye is mixed with a composition comprising at least one oxidizing agent and applied onto hair and rinsed off from hair with water after processing 5 to 45 min at a temperature of 20 to 45°C and towel dried,b- the towel dried hair is put on curlers,c- an aqueous composition comprising at least one reducing agent is applied onto hair and rinsed off from hair with water after a processing time of 2 to 30 min at ambient temperature and towel dried,d- a composition comprising at least one oxidizing agent is applied onto hair processed for 2 to 15 min and optionally rinsed off from hair with water and optionally towel dried, ande- an aqueous oxidative colouring composition based on at least one oxidative dye precursor and optionally at least one coupling substance is mixed with a composition comprising at least one oxidizing agent and applied onto hair and rinsed off from hair with water after processing 5 to 45 min at a temperature of 20 to 45°C and towel dried and dried with a dryer or left to dry in the air.
