Former premier Dr Mahathir Mohamad and his wife Dr Siti Hasmah Ali made a surprise visit at Bersih 4, sending a jolt of excitement through the crowd gathered at the Dataran Merdeka and Kuala Lumpur City Hall (DBKL) intersection.
The couple, who arrived about 7.30pm, was swarmed by protesters who attempted to shake hands and snap photographs with the pair.
Media personnel also rushed to the scene.
Mahathir, who was a wearing a gray bush coat, was escorted by PKR vice-president Tian Chua and the former premier's bodyguards.
Ironically, Tian Chua was one of Mahathir's biggest critics when his administration clamped down on the Reformasi protest following the sacking of Anwar Ibrahim in 1998.
After spending several minutes, Mahathir and Siti Hasmah left in a car.
Earlier in the afternoon, Mahathir attended an event in Pasir Gudang, Johor, where he told reporters that he was still thinking about attending the rally in Kuala Lumpur.
His presence at the event titled "Malaysia hari ini: Ke mana kita" (Malaysia today: where are we heading) was met with a rousing applause and cheers of "Hidup Tun".
Some 3,000 people attended the event at the Pasir Gudang indoor stadium.
The former premier however admitted that he was not fond of demonstrations as there were other means to solve problems.
"But these channels have been blocked. If we lodge reports, we will instead be investigated. This is not the police's fault. It's the fault of the people on top.
"That person who is above the laws and constitution who has violated the rule of law. That person is responsible for what Malaysia is today," he said, without mentioning names although it was clear that he was alluding to Prime Minister Najib Abdul Razak.
Mahathir added this the reason why there are demonstrations held in such large scales.
Meanwhile, Mahathir was also asked by a member of the audience, who had recently graduated, on students not being allowed to participate.
The former premier quipped that students should join the rally while donning a mask.
"Don't wear a yellow shirt, but participate in Bersih, wear a mask," he said to laughter from the audience.
To another question from the same person regarding the unemployment rate, Mahathir replied: "Unless you get rid of Najib, your unemployment problem will not be resolved."
"This is the problem with him, he doesn't know what he's doing," he said.