Up to 120,000 football fans are preparing to follow their team's FA Cup dreams as Cardiff hosts the contest's two semi-finals for the first time.
Mark Hughes' Blackburn Rovers will take on Arsenal at the Millennium Stadium in a 1215 BST kick-off on Saturday.
And Newcastle United play Manchester United at 1400 BST on Sunday for the right to return in the final on 21 May.
South Wales Police have warned supporters to avoid delays by planning their journeys in advance.
And fans travelling by rail from London are advised to check train timetables due to ongoing engineering works at the Patchway Tunnel near Bristol.
Cardiff has hosted the FA Cup final since 2001, but this is the first time it will host the semi-finals, which have traditionally been played at neutral grounds in England.
However, this is the last year that the Millennium Stadium will host any part of the tournament, as the new Wembley stadium is due to be completed in time for next year's competition.
Traffic Wales hotline 0845 60 2 60 20
City centre road closures 1030-1615 Sat and 1200-1800 Sun
Park-and ride: Arsenal/Man Utd, signs from M4 jct 33: County Hall, Leckwith, Queensgate
Blackburn/Newcastle, signs from M4 jct 29: Cathays High School, Companies House, UHW, Portmanmoor R Ind Est
Matches: (Sat) Arsenal v Blackburn, gates open 1045, kick-off 12.15; (Sun) Man Utd v Newcastle, gates open 1230, kick-off 1400.
Tickets: Tickets unavailable to buy in Cardiff.
Earlier this week, a survey claimed that Cardiff's staging of big sporting events was having a significant impact on the environment, due to the amount of travel and waste generated by supporters.
Researchers who interviewed fans at last year's FA Cup final found that fans consumed a total of 370,000 pints of beer and lager and 38,000 pasties during their visit to the city.
They calculated that the "ecological footprint" of the final was 3,051 football pitches - which relates to the amount of land that would have to be cultivated to match the amount of energy used on the day.
Chief Superintendent Bob Evans, the event commander from South Wales Police, said officers were ready for the challenge of hosting the two matches this weekend.
"Our message to supporters remains clear; avoid delays by planning your journey to the match, and enjoy your visit to Cardiff safely and responsibly," he said.
"As ever we would recommend those travelling to come by coach or mini-bus, and for those driving to make use of our park and ride facilities."
Road closures in Cardiff city centre will be in effect during both semi-finals.