The "Brexit coin" had twice been pulled from going into circulation when the country missed two proposed dates for leaving the EU.
A million coins had to be melted down last year after the 31 October deadline came and went. Before that, 1,000 prototypes were scrapped when the original exit date of 31 March was not met.
However, collectors and Brexit fans will finally be able to get their hands on the coins on Friday – when, at 11pm, the UK will officially leave the EU – as the Royal Mint releases them into circulation.
They are inscribed with the date 31 January and the words, “peace, prosperity and friendship with all nations". About 3 million will be circulated initially, with another 7 million planned for later in the year.
Mr Javid, whose role as chancellor also makes him master of the mint, said: “Leaving the European Union is a turning point in our history and this coin marks the beginning of this new chapter."
In addition to the unveiling, it was also revealed that there will be a light show in Downing Street to mark the day.
A countdown clock will be projected on to its black bricks from 10pm, while government buildings in Whitehall will also be showered in red, blue and white light. Union Jack flags will line Parliament Square and The Mall.
The 50-pence piece will not be the UK's first coin relating to Europe: it also minted one in 1973 to celebrate joining the European Economic Community.
As part of the launch, the Royal Mint will open its doors for 24 hours to let people strike their own commemorative Brexit coins.
Those who are especially keen to get their hands on one of the coins, meanwhile, can register their interest online.