The Chief of the Army Staff (COAS) (unofficially known as the Army Chief) is a statutory position in the Indian Army held usually by a four star general. As the highest ranking officer to serve solely in the Indian Army, the chief is the professional head of the ground forces and a key adviser to the Minister of Defence. The COAS, in a separate capacity, is also a member of the National Security Council and thereby an advisor to the president and the prime minister. The COAS is typically the most senior army officer in the Indian Armed Forces, unless the Chief of Defence Staff and/or the Chairman Chiefs of Staff Committee is an army officer.