Tourism, business and civic leaders have said they are "delighted" that Cardiff will host another FA Cup final.
The English FA switched the 13 May game to Cardiff because developers of the new Wembley Stadium could not guarantee it would be ready in time.
Around 70,000 fans will arrive with a ticket for Britain's most prestigious football competition while up to 40,000 will descend on the city's' pubs.
And they are expected to spend up to £3.5m between them.
Millennium Stadium chief executive Paul Sergeant said on Tuesday he was "ecstatic" at the news.
"The FA took the prudent measure of reserving the Millennium Stadium, to stage the cup final, way back last August," he told BBC Radio Wales.
"They took some criticism for it at the time but, you know, what a great step it was on their behalf, to reserve the place.
"It is probably one of the worst kept secrets of the last eight or nine months but we're hearing now that it's going to come to us, so bring it on."
Cardiff City centre manager Paul Williams said: "This is one we should embrace because it is going to be the last one.
"It means a lot in terms of economic benefits as it has done every year since its been held in Cardiff.
Wembley contractors Multiplex said they were "disappointed" by the decision
A "delighted" Paul Jenkins, head of tourism for Cardiff Council, said hosting the FA Cup over past years had contributed to a rise in visitor numbers outside of the football season.
"Evidence has shown that people come to the FA Cup and then return, using the city for mini-breaks or a holiday destination," he said.
Meanwhile, some hotels said they are already fully booked for that weekend as pubs and clubs confirmed they are now putting plans in place.
Claire Musa from the Big Sleep hotel said they have been fielding booking calls ever since the announcement early on Tuesday.
"I started work at seven o'clock this morning and we had 13 rooms left for that weekend - the very first phone call we took booked all 13."