They are words likely to bring a look of trepidation to the faces of Prince George's parents.
Prince Harry said yesterday that one of his missions would be to make sure his newborn nephew "has fun".
But with his track record of partying misdemeanours, the Duke and Duchess of Cambridge might feel inclined to ensure Uncle Harry does not exert too great an influence on his replacement as third in line to the throne.
However, if they were in need of reassurance, the Prince, 28, said he would also make sure that his nephew "has a good upbringing" and would "keep him out of harm's way".
He added that he would be happy to babysit for his brother, if the Duke could afford the fee.