Prior to the 14th general election, the pair did the unthinkable – shook hands and forged an alliance.
Dr Mahathir Mohamad was slated to pass the leadership baton to Anwar Ibrahim within two years of becoming prime minister. This timeframe, however, has been subjected to constant tweaks since then.
Anwar, 70, has repeatedly mentioned that he is not in a rush. The last time he was said to be impatient to succeed Mahathir, he landed behind bars with a black-eye.
Speculation has been making the rounds that Anwar's future as prime minister is not exactly cast in stone and there are those within Mahathir's circles who do not trust him.
It appears that Mahathir himself has an issue of trust concerning his heir-apparent-turned-nemesis-turned-heir-apparent.
In an interview with CNN, the 93-year-old leader said: "I have to trust him – whether I like it or not. I can't be here all the time.”
Questioned on the time-frame with regard to Anwar succeeding him, he replied: "If the condition for us (Anwar and him) working together is my serving as prime minister for two years or three years, for me that is not important.”
"I will abide by the wishes of the people," he added.
However, Mahathir also said if Malaysians wanted him to serve beyond the period agreed with his Pakatan Harapan partners, he would do so.
Meanwhile, the prime minister claimed that he inherited a government replete with corruption and officials who cannot be trusted.
"From outside we saw the damage, but we never expected the damage to be so extensive. Most of the top echelon in the government are corrupt," he said.
Mahathir also said that he has to work with people who are suspect.
"It's a very difficult job, if you don't work with people you trust, you don't know whether what you want them to do will be done or not," he said.