胡佳
Mathew Helm (born 9 December 1980) is an Australian diver who won the silver medal at the 2004 Summer Olympics in the men's 10-metre platform. He was in first place at the end of the preliminary round and the semi-finals, but was passed by Chinese diver Hu Jia in the finals. In the 2006 Commonwealth Games held in Melbourne, he won the 10-metre platform gold medals in the Individual and Syncro.