Sharif had a telephonic conversation with Zardari today and invited him for the luncheon meeting tomorrow at the Prime Minister's House.
Zardari, co-Chairman of Pakistan People's Party (PPP), is currently in Karachi. He mostly lives in Dubai since stepping down last year at the end of his five-year term as the President.
Zardari's spokesman Farhatullah Babar said the two leaders today talked to each other and agreed to meet tomorrow.
Zardari has won admiration because his party was the first ever to complete its allotted five-year term in coup-prone Pakistan and hand over power to Sharif in a smooth transition.
Also Read
It is expected that the two leaders will discuss the standoff between the government and thousands of protesters camping in Islamabad, calling for Sharif's ouster.
Pakistan Tehreek-i-Insaf chief Imran Khan and cleric Tahirul Qadri are protesting alleged vote rigging in polls last year and demanding Sharif's resignation and holding of fresh polls.