Former presidential candidate Tan Cheng Bock was seen having breakfast with Mr Lee Hsien Yang at a hawker centre in West Coast yesterday morning.
They were at the West Coast Market and Food Centre at Block 726 Clementi West, which is in Dr Tan's former Ayer Rajah constituency when he was an MP with the People's Action Party from 1980 to 2006.
When approached by The Straits Times, Mr Lee, the younger brother of Prime Minister Lee Hsien Loong, said: "We were just here to have breakfast."
He and Dr Tan then left the hawker centre.
Posting on Facebook later that morning, Dr Tan said: "We wanted to catch up with each other as we have not met for quite a while."
He said he suggested going to the hawker centre instead of "some fancy restaurant", and that Mr Lee was all for it as he missed local hawker fare in the heartland.
"We had porridge and coffee with yu tiao (dough fritters). It was a good breakfast, not only the food, but (also) the sharing we had on world affairs and the current state of politics in Singapore," Dr Tan wrote.
He said many greeted them warmly, and some took photos with them. "We were touched by their warmth and encouragement. I will be having more breakfasts and lunches with friends regularly in the heartland," he added.
Dr Tan had contested in the 2011 Presidential Election, in which he lost to former president Tony Tan Keng Yam by 7,382 votes.
In July, he was invited by opposition parties here to lead a proposed opposition coalition.
Dr Tan later said that at the age of 78, he has just a "small window of opportunity" to effect change in Singapore politics. He also said he thought he must help but had not decided in what capacity.
Mr Lee Hsien Yang, formerly chief executive of Singtel, stepped down as chairman of the Civil Aviation Authority of Singapore at the end of June.
In April, he and his sister Lee Wei Ling took issue with a report by a ministerial committee looking into future options for founding prime minister Lee Kuan Yew's home at 38 Oxley Road. The siblings said it did not accurately represent the wishes of their father, who died in 2015.
Residents interviewed were mixed on the idea of Dr Tan returning to politics. The next general election is due by January 2021.
Technician Keith Chua, 27, said his choice of MP will be based on policies rather than personality.
Business owner Nora Tan, 60, said she had no complaints about the current MPs in West Coast GRC, which absorbed the former Ayer Rajah SMC in 2006. The West Coast GRC MPs are Minister for Communications and Information S. Iswaran, Mr Lim Hng Kiang, Ms Foo Mee Har and Mr Patrick Tay.
She added that should Dr Tan return to the area, his team would have to show that they have something different and better to offer.
Housewife Goh Hui Suan, 49, said she had supported Dr Tan for president and would have voted for him if he had run for that office last year.
"If he runs for MP, I would be happy to vote for him," she said, adding that he comes across as someone who cares sincerely about Singapore.