The pair are two shots ahead of the chasing pack after five birdies on the back nine helped Aiken to the day's lowest round of 63 and a 54-hole total of 198.
Johannesburg-born Walters hit 64 to also sit 17 under-par going in Sunday's final round of the European tour event.
Walters birdied three of the first six holes to quickly catch up with the overnight leaders and then made four more in a row from the eighth - the last courtesy of a remarkable 40 footer.
Korean Jeong Jin is on his own in third place on 15-under-par with Roope Kakko of Finland a further shot back.
Overnight leaders Edoardo Molinari and Craig Lee slipped as the Italian former Ryder Cup player failed to improve on his 11-under-total after two rounds and Scotsman Lee stumbled to a two-over-par tally of 74, eight shots off the pace.
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