His parents, Chris Gard and Connie Yates, successfully raised money in hopes of bringing their son to the U.S. for an experimental treatment, but doctors at the Great Ormond Street Hospital in London, where Charlie has been since October, argued in court that it was not in their patient's best interest.
Last week, Great Ormond Street Hospital (GOSH) released a copy of its latest submission to the High Court.
The visit has been arranged as part of the latest stage of a court fight, brought by Charlie's parents Connie Yates and Chris Gard, from Bedfont, south west London, over whether he should be given experimental treatment in America.
Medical experts are scheduled to gather today at Great Ormond Street Hospital in London, where 11-month-old Charlie is being cared for.
The hospital gave Hirano, a doctor and professor at Columbia University Medical Center, an honorary contract, which gives him the same status as its own physicians.
They boy's parents are fighting an emotional legal battle with Britain's most famous children's hospital over whether trying an experimental treatment is in Charlie's best interest. After much debate in court on Friday over whether Charlie's parents will be present for this, the Judge announced that Yates will be allowed to attend.
They do not believe that Charlie has any chance of surviving his critical illness and that life-support treatment for the child should stop.
But Dr Hirano, 55, believes his experimental theory could give Charlie "11% to 56% chance of clinically meaningful improvement".
But judges in several courts - most recently the European Court of Human Rights - told his parents that taking Charlie overseas was not in his best interests.
He will meet with doctors and medical experts at the hospital to discuss his treatment.
In April a judge ruled in favour of Great Ormond Street, saying Charlie should be allowed to die with dignity.
Charlie Gard's mother has said she wrote to Pope Francis asking him to intervene, but did not request United States President Donald Trump's help, the Press Association reported.
Litigation is due to resume after Dr Hirano's meetings - this is likely to be Tuesday or Wednesday.