The long-awaited all-night Tube service in London will be launched on August 19 on two lines, Mayor Sadiq Khan announced.
The 24-hour trains were due to start last year but no agreement was reached with unions over pay and conditions, which led to strikes.
The first all-night Tube services will run at weekends on the Central and Victoria lines. Night services on the Jubilee, Northern and Piccadilly lines will follow in two separate phases later in the autumn as new Tube drivers complete their training and final preparations are made.
Around 200 part-time drivers are currently taking part in a 14-week training programme for the new service.
The mayor said: "The Night Tube is absolutely vital to my plans to support and grow London's night-time economy - creating more jobs and opportunities for all Londoners. The constant delays under the previous mayor let Londoners down badly.
"I have made getting the Night Tube up and running a priority, and London Underground has now confirmed that services on the first two lines will launch on August 19."