Cape Town - Former Springbok scrumhalf Joost van der Westhuizen, will attend the match between Saracens and Western Province at Allianz Park, London, on Sunday.
The scrumhalf, capped 89 times by South Africa, is raising awareness for Motor Neuron Disease, a condition he has been fighting since 2011.
Both teams have named their squads for the game which will be live on BT Sport in the UK and Supersport in South Africa.
Kick-off is at 15:00 (SA time).
Forwards; Richard Barrington, Mouritz Botha, Kelly Brown, Petrus Du Plessis, Juan Figallo, Will Fraser, Jamie George, Jim Hamilton, Rhys Gill, Alistair Hargreaves (C), Ernst Joubert, Scott Spurling, Jackson Wray.
Backs; Chris Ashton, Neil De Kock, Mike Ellery, Charlie Hodgson, Nils Mordt, Ben Ransom, Ben Spencer, Tim Streather, David Strettle, Chris Wyles.
Western Province squad:
Manuel Carizza, Demetri Catrakilis, Kurt Coleman, Juan de Jongh (captain), Rynhardt Elstadt, Gerbrandt Grobler, Nic Groom, Pat Howard, Oli Kebble, Jean Kleyn, Vincent Koch, Dillyn Leyds, Wilco Louw, Bongi Mbonambi, Sikhumbuzo Notshe, Scarra Ntubeni, Michael Rhodes, Louis Schreuder, Jaco Taute, Michael van der Spuy, Jurie van Vuuren, Kobus van Wyk, Alistair Vermaak, EW Viljoen