The city council is planning a day of celebrations next month to mark the official ceremony. No date has yet been earmarked.
The FA Cup will be on show and the council hopes Harry and the boys will parade on a red carpet in Guildhall Square.
Council leader Gerald Vernon-Jackson wants thousands of fans to turn out to celebrate Pompey's achievement.
'This is not just about the city council, this is about the whole city and I think the whole city should be involved,' he said.
'We want to recapture some of the magic from the parade that took place when Pompey brought the FA Cup to the city for the first time.
'I am hoping we can get some very special things lined up – I am hoping we can get lots of people involved in sharing their thoughts of the day the FA Cup came to Portsmouth.'
The Freedom of the City is one of the highest honours the council can give.
>>> Take a look at our Pompey blogs and get involved. Click here.The ceremony itself will take place in the Guildhall but there are plans in the pipeline to broadcast it on to the giant screen outside so that the crowds can watch.
Councillor Vernon-Jackson said he would invite people who had attended the 1939 FA Cup Final – when Pompey beat Wolves 4-1 – to take part in the proceedings, along with people who played a part in organising and supporting the FA Cup parade earlier this year.
Tory leader Steve Wemyss said: 'As a lifelong Pompey fan I will be there.
'I want to see Harry and the team rewarded for their efforts which led to such a great achievement that really put Portsmouth on the map.
'I would imagine the crowds will be out in force again.
'It is a big deal and it will be great to take part in the celebrations.'
The full article contains 353 words and appears in The News newspaper.