Road closures will be in place on Friday as 40,000 people head to Cardiff for a Justin Bieber show.
The Canadian singer will appear at the the Principality Stadium, with the gates opening at 17:30 BST and event ending after 22:30.
Some nearby roads will be shut for periods between 18:00 and 23:00,
Those coming by car have been urged to use a park-and-ride at Cardiff City Stadium, as city centre car parks are expected to be busy.
Westgate Street, Park Street and Scott Road will shut at 18:00 and closures could be expanded if necessary on safety grounds.
After the event, the closures will be extended to cover parts of Cowbridge Road East, Castle Street, Duke Street and Wood Street.
Arriva Trains Wales advised customers Cardiff Queen Street Station will shut at 21:45 and there will be a post-event queuing system at Cardiff Central.
There will be limited extra services after the concert, with customers urged to return directly to Cardiff Central when the show ends.