De Klerk made his test debut for the Springboks on 8 June 1974 at Newlands in Cape Town against the touring British Lions team, captained by Willie John McBride.
[2] In subsequent years it was often a choice between de Klerk and Van Heerden for the number 4 lock position in the Springbok team.
De Klerk's last test match was against Ireland on his 31st birthday, 6 June 1981 at Kings Park Stadium, Durban.
The four other players named, were two members of the 1972 England team that toured South Africa, namely Sam Doble and John Pullin, as well as the South African flanker Jan Ellis and future Springbok Carel Fourie.
He was elected president of the Golden Lions Rugby Union in July 2009 and held this position until his retirement in August 2018.