Instead of closing at 5pm, the food court, bar and stalls will continue trading until late. Fruit and vegetables stalls will be open until 7pm.
This is the first time the popular markets, which opened in 1980, have traded into the evening and organisers are putting on plenty of entertainment.
Taking the stage will be Joanna Carron-Brown, Kimberley Heberley, band eleven eleven, Robert Hinton with Scott Barnett and Heath Marshall.
Children (accompanied by an adult) can enjoy face-painting, a bouncy castle and more, plus spot prizes through the night.