The full Night Tube and Overground service will run for the first time ever tonight as rail services are linked up with the Victoria line.
Transport for London said thousands of passengers will benefit from the extended Night Overground to Canonbury and Highbury and Islington, which will now run on overnight on Fridays and Saturdays.
It will connect the Overground and Victoria line for the first time, easing journeys for those travelling to and from north and east London.
The new service is an extension on the Night Overground that already runs between Dalston Junction and New Cross Gate.
It is the final amendment to the Night Tube map for the foreseeable future.
Mayor of London Sadiq Khan said: “Following our hugely successful launch of the Night Tube, I’m delighted that we will be able to extend the Night Overground service to help even more Londoners.
“This extension will connect the Night Overground to the Night Tube.
“These night-time services are providing a huge boost to our economy and a safe and reliable way for people to travel across the capital, helping all those working hard during the night or out enjoying everything the capital’s nightlife has to offer.”
More than nine million journeys were made on the overnight service in its first year, according to TfL.
Jonathan Fox, TfL’s director of London rail and sponsored services, said: “The extension of Night Overground to Highbury and Islington will make life easier for thousands more Londoners and visitors, opening up a new late night connection between east and north London and boosting the night time economy.
“It builds on the great success of the Night Overground services we introduced last year, which have already seen more than 35,000 customers.”