Kalu, who shared photos from the visit on social media, said the Biafra leader does not belong in Kuje prison.
He described Kanu as his “brother” and stated that his freedom was of “utmost concern” to him.
“Today, I visited Mazi Nnamdi Kanu in Kuje Prison and we engaged in a very long discussion. Kanu is my brother and a son of the soil. He shouldn’t be where he is because Kuje Prison is not his home.
“It is therefore my utmost concern to see him regain his freedom like every other Nigerian,” Kalu wrote.
Kanu, in a recent protest of Justice Binta Nyako’s decision to shield witnesses that would testify against him, said Nigeria will collapse when he gives his testimony in court.
“Buhari went on national television to accuse me in public and he wants to try me in secret. I will not allow myself to be subjected to this kind of trial.
“By the time I am through with my testimony there will be no Nigeria. What kind of secret trial? This is not a Sharia Court but common law court,” he had said.
Kanu is facing 11-counts of treason and terrorism brought against him by the federal government.
The Radio Biafra director has been in detention since October 2015 when he was arrested by operatives of the Department of State Services (DSS) in Lagos.