Jason was last in South Africa when he was a player with England in 2007. But, having arrived on Monday, Jason will be in the country for three weeks building up to the first Lions Test match on June 20.
Jason will be pulling his boots back on to coach this time, with hundreds of children who have recently been introduced to rugby by HSBC and TAG at St John's College.
Speaking at the event Jason said, "I have been fortunate enough to be involved with the HSBC Rugby Festivals back in the UK & Ireland which have involved over 60,000 children in England, Ireland, Scotland and Wales.
"The focus in the UK was on emerging rugby schools which is of particular interest to me given my background in rugby. Over here in South Africa, the HSBC office has been running a TAG rugby programme introducing rugby to townships across the Gauteng region. The children here are new to rugby but are so enthusiastic. It's very encouraging and I am confident rugby will continue to be part of the childrens' lives."
Jason was coaching at the culmination of a three-month HSBC programme involving 20 different township schools across Soweto, Alexandra and Mamelodi.
Giles Morgan, group head of sponsorship for HSBC said, "Working with children in local communities is an extremely important element of HSBC's Lions sponsorship.
"It is fantastic that our Africa office have got so involved in the TAG Rugby programme, volunteering their time to coach the children - over 80% of whom had never played rugby before. I really hope that the children have enjoyed being coached by a former British & Irish Lion and continue to play rugby in the future."
Tuesday's festival was the second of four festivals that HSBC is running across South Africa during the 2009 Lions tour.