"I don't know what we'll talk about with President Clinton," Mr Sobchak said, adding that he had met former US presidents Ronald Reagan and George Bush several times.
Mr Clinton is scheduled to arrive April 18 in the evening on his way to Moscow's G7 nuclear security summit April 19-20.
The visit will be short and purely social. American Consulate spokeswoman Vera Savko said the trip was a private visit and arose from Mr Clinton's personal desire to see the city.
Plans include a morning visit to Piskarevskoye Cemetary, where about half a million victims of the Siege of Leningrad are buried.
Mr Clinton is expected to give a short speech at the cemetery.
Both Mr Sobchak and Deputy Mayor Vladimir Putin are scheduled to accompany Mr Clinton during his visit.
A US Information Service spokesman said special security measures would be taken in the city. "US and Russian security services are working together," he said.
Inna Vasilevna, a spokesperson for the GAI, confirmed that special traffic patterns would be enforced, but promised there would be no traffic jams.
"There are never jams when important people come visit," she said.
Early figures had the president's 18-hour trip running up a $3 million bill, but Ms Savko would not confirm that amount.
She said most funds would be spent on the president's plane and wages for those accompanying Mr Clinton.
Mr Clinton is also scheduled to visit the Hermitage and possibly the Russian Museum.
On Thursday night, Mr Clinton and his team of advisors, controlers and journalists will be farmed out among three hotels.
Ms Savko confirmed Mr Clinton would be staying at the Grand Hotel Europe, while other White House personnel and journalists will stay at the Nevskij Palace and Primorskaya Hotels.
Security is a concern for both Russian and US security services after a shooting at Nevskij Palace Hotel that left three people, including a Scottish lawyer, dead.
Natasha Belik, head of public relations at Nevskij Palace, said security had been increased substantially after the shooting.
In addition, she said the White House would provide extra security for the personnel staying at the hotel.
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