"I'm supposed to speak to Graeme a bit later, just to try to get some ideas of how he did things when he was over here because he was a very successful captain. I'm looking forward to that conversation."
If anyone knows how to win in Australia, it is Smith. He is the only South African captain to take a team to victory in Australia, and he did it twice. Smith's success seemed to stem from the bat, not even a broken arm getting in the way of it, but the real secret to what he achieved in Australia was in the mind.
Under Smith, South Africa were no longer intimidated by an opposition that had long dominated them. They believed they could be better and they were. So much so that they even scared themselves.
"For a year or so, we were trying to play in the shadow of the team that was there," du Plessis admitted.
The shock of Smith's retirement in 2014, and the proximity of it to Kallis' retirement three months before, meant that South Africa lost significant experience in a short space of time. Although their newly-appointed captain AB de Villiers had played a decade of international cricket, he did not have any background in leadership. South Africa struggled for direction and it was only after de Villiers grew into the job and then passed it to du Plessis - albeit only temporarily - that they started to find themselves.
They have created a new identity, with their "own goals of what we want to achieve," and now that they are sure of what those are, they are ready to go back and seek assistance.
"The most important thing for me as a leader is to put your ego aside and try and ask and learn as much as you can because there's a lot of valuable information out there," du Plessis said.
To that end, du Plessis has also been in touch with the regular captain and his childhood friend, de Villiers, who he says is "enjoying life in South Africa but missing us." If de Villiers had given du Plessis any tips, he didn't share them with the media, but they are likely to be particularly valuable in Perth where de Villiers raced to 169 off 184 balls the last time he was here, helping South Africa build a match-winning total.
The lessons of de Villiers' innings will also come from Smith, who knows that without players who can provide momentum in the way de Villiers and Hashim Amla did in 2012, and Duminy did in 2008, he may never have won. Similarly, without Dale Steyn, Smith would not had the firepower to fight Australia and he will remind du Plessis of the importance of managing the spearhead so he remains as sharp as possible.
Smith usually waited until Steyn was fired up and ready to explode, before asking him to put on a show. If Steyn got angrier or more aggressive during the performance, Smith would not interfere. He left Steyn to own the stage and inevitably, Steyn responded.
Du Plessis will probably do the same thing but he also wants Steyn to school the rest of the attack, something he has already started doing.
"He has really stepped up in terms of working with the young guys and in team meetings and discussions, he has led vey well," du Plessis said. "Hopefully he can stay strong right through the series. We need him. Hopefully he can bowl at good intensity and for long periods of time."
Smith may have tips on how to keep Steyn's workloads from aggravating the shoulder problem that caused him to miss most of last summer, and about when to use him in ways he can work up both speed and swing. But the biggest tip Smith will pass on to du Plessis is that none of the above will be possible unless the team has good guidance and a strong example to follow. That example has to be du Plessis, a particularly tough ask for a young leader.
When Smith first won in Australia he had already been captain for five years. Du Plessis has not even done it for five Tests. Still, he sees himself as being thrust into the role at the best time.
"I am older, more mature and understand myself better as a leader. I have got the balance better. I understand what it takes to be a better leader," he said.
He also has the advantage of knowing what it is like to single-handedly shoulder responsibility, as he did in Adelaide and, like everyone else in his squad, he does not have any memory of losing in Australia.
"I haven't been on the other side. I assume that it helps," du Plessis said. "Confidence plays a huge role in cricket. When you come up against good teams like Australia, you need everything. My first thought walking into Perth was of winning four years ago. You'd rather have good memories than bad memories."
And when he calls Smith, there will only be talk of the good ones.