Highways England has announced that it will be temporarily opening the lane on the A55/A483 roundabout to allow for additional traffic during the three-day event between Wednesday 6 and Friday 8 May.
A total of 65,000 people from across the North West and Wales are expected to attend the festival, which first took place in 1766.
The roundabout will then be reduced to two lanes until Sunday 28 June while work takes place to complete a £6 million project to upgrade the junction.
The number of lanes through the roundabout is currently reduced to two, which will be doubled to four when the scheme is complete. New traffic lights will also use sensors to control the flow of vehicles through the junction.
The scheme had been due to be finished next month but has been extended for additional bridge strengthening work and also to allow the third lane on the roundabout to be opened during the May Festival.
Work to install street lights at the roundabout has now been rescheduled to take place overnight in July so that the lane restrictions can be lifted as soon as possible.
Contractors have already installed traffic lights at the A483 junction with Rough Hill, just south of the A55 roundabout, and at the junction linking the A483 to the B5445 Wrexham Road, replacing the mini roundabout. These traffic lights will be synchronised with the new lights at the A55/A483 Posthouse roundabout when they go live.
A separate scheme has also been completed to provide CCTV cameras at the roundabout and a new footbridge, which has been lowered into place over the A55, is due to open in the next few weeks.
Drivers are being advised to use alternative routes while the work takes place to upgrade the junction. Motorists travelling to and from the southern part of Chester can use the A534 and the A41, and those heading to and from the northern part of the city can use the A550, A55, A494 and M56.
More details on the scheme are available on our road project page, where drivers can also sign up to receive email alerts.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.