Sharif headed the Pakistan Muslim League government when Musharraf ousted him in 1999. He and Bhutto, who heads the Pakistan People's Party, are scheduled to meet this week in London to implement their democracy charter ahead of elections expected next year in the country.
However, recent media reports have alleged Bhutto, another bitter critic of Musharraf, had been talking to the Musharraf government, reports the Press Trust of India.
Sharif was quoted as saying he would ask her about these alleged talks.
"It will not be wise to make decisions on media reports," Sharif told Pakistan's English newspaper Dawn.
"I am sure she will dispel these rumors," he said.
Both Bhutto and Sharif, who live outside Pakistan, have vowed to return to the country to campaign for the 2007 elections.
Sharif said he did not believe Bhutto would enter into a deal with the government after signing the charter of democracy.