Onyanko Club
Iwai was a member of the all-girl pop group Onyanko Club (from 21 June 1985 until 31 August 1987), and she was the shortest of all the members at 150 centimetres (4 ft 11 in). She was also half of the pop group Ushiroyubi Sasaregumi, a spin-off group of Onyanko Club.