Fleetwood defeated Sweden's Marcus Kinhult at the first extra hole of a play-off at the Gary Player Country Club in November 2019 to claim his fifth DP World Tour title.
The tournament was cancelled in 2020 and 2021 due to the Covid-19 pandemic and Fleetwood has surprisingly failed to follow up his success at Sun City with any further victories.
"This is a very special event for me," the world number 25 said. "I grew up watching this event with my dad every year. I love the history behind it and the winners.
"When you walk down the ninth hole on the left and you see all the winners from all the years on that walkway, I often thought it would be great to add my name on there.
"To get that win was very cool and now I've defended it longer than anybody. I think we're all excited to come back."
Fleetwood is the highest ranked player in the field but is just one place ahead of New Zealand's Ryan Fox, who has won twice this season and can overhaul Rory McIlroy at the top of the DP World Tour rankings ahead of the season-ending tournament in Dubai with another victory this week.
"I see these next few weeks as an opportunity, I've got nothing to lose," Fox said. "I'm still going to have my best year out here regardless.
"I've got a pretty good player ahead of me to chase down in Rory, and a pretty good player behind me in Fitz (Matt Fitzpatrick). It's hard to describe because it's not a position that I thought I would be in at the start of the year.
"The last couple of years have been pretty tricky in places. I haven't felt like my golf game has been too far away, but the results haven't been coming and nothing like this looked like it would happen.
"I'm proud to be in this position and proud to have a couple of wins and contend more this year than I have in my previous years combined.
"You list the challenges around here and it's a long list. It's very narrow in places, greens are small and lots of tricky pin placements.
"Add in swirling winds around the volcano crater, altitude and a fair bit of heat. It's a golf course that's hard to figure out and I haven't done well at all on my previous attempts."