Mr Sessions, who wrote to the Senate Intelligence Committee at the weekend, has asked that the hearing be open.
He will face questions about undeclared meetings with Russian officials and the president’s firing of the FBI chief.
Media reports last week said Mr Sessions had offered to resign because of tensions with the president.
Tuesday’s hearing has been scheduled for 14:30 local time (18:30 GMT).
America’s top justice official will be the most senior government official to testify before the Senate committee, which is looking into allegations that Russia had tried to meddle in last November’s election.
It is one of several congressional panels that, along with a special counsel, is also investigating whether any Trump campaign officials colluded with the alleged Kremlin plot.
The White House has rejected any collusion with Russia, which has denied meddling in the US election.
In his letter on Saturday, Mr Sessions said: “It is important that I have an opportunity to address these matters in the appropriate forum.”
He had been due to appear before the Senate and House appropriations subcommittees on Tuesday, but said his deputy would attend those hearings instead.
In testimony last week, Mr Comey suggested Mr Trump had fired him to undermine the Russia inquiry.