If you see people taking a bath in Cathedral Square this afternoon, just know it’s all for a good cause.

Heart Kids Canterbury is holding its annual fundraising event, the Heart Stopper Challenge, raising money for Heart Kids NZ.

Twelve teams have entered this chilly challenge of dressing up and taking the plunge into freezing cold water for six minutes. The ice water represents the many Heart Kids who have ice put in their chest during open-heart surgery.

Registrations start at 2pm, with the event starting at 3pm.