Earlier the office said that Duda's attendance at the funeral will depend on the wishes of Adamowicz's next of kin.
"President Andrzej Duda will attend the funeral ceremony of tragically deceased Gdańsk Mayor Paweł Adamowicz. In connection with this, he is in permanent touch with the prime minister and Gdańsk City Hall," the president's website informed on Wednesday evening.
Also expected at Adamowicz's funeral are European Council head Donald Tusk, PM Mateusz Morawiecki, Deputy PM Piotr Gliński and Health Minister Łukasz Szumowski.
The funeral ceremony will begin at noon on Saturday with a holy mass in Gdańsk's St. Mary's Basilica, where Adamowicz will be laid to rest.
Duda has decreed a period of national mourning for Adamowicz from 5:00 pm on Friday to 7:00 pm on Saturday.
On Sunday evening Gdańsk Mayor Paweł Adamowicz was stabbed by a recently released convicted criminal who rushed onto the stage during the Great Orchestra of Christmas Charity finale in Gdańsk. The mayor suffered severe cardiac and abdominal injuries. Doctors reanimated Adamowicz on the spot and then transported him to the Medical University of Gdańsk hospital, where he underwent five hours of surgery. Adamowicz died from his injuries on Monday afternoon without regaining consciousness. (PAP)