<Li> Denise--Dennis' alter ego . Denise is French and speaks very little English, Dennis and Lisa create her when Dennis tries on Lisa's dress which she made . She is played by Billy Kennedy . </Li> <Li> John Simms--Dennis's 14 - year - old brother who is a pupil at Elm Forest School . He is played by Oliver Barry - Brooke </Li> <Li> Lisa James--A 14 - year - old . She is the prettiest girl in the school and is adored by everyone, she is a pupil at Elm Forest School . Lisa loves Vogue, fashion, dresses and shoes . She is played by Temi Orelaja . </Li> <Li> Miss Windsor--A French teacher . She is played by Jennifer Saunders . </Li>

Who plays lisa james in the boy in the dress