Bus passengers in London will be able to make an additional journey for free within one hour of beginning their first, the capital's newly-elected mayor Sadiq Khan has announced.
The Hopper fare - which was a key part of Mr Khan's manifesto - will be introduced in September.
It is hoped the move will particularly benefit people on low incomes who rely on the bus network, and those who live or work in areas that are not well served by Tube or rail services.
Transport for London's ticketing technology is also being upgraded to allow unlimited bus transfers within an hour by the end of 2018.
Bus fares in the capital are £1.50 per journey, with a daily price cap of £4.50.
Khan said: "My dad drove the number 44 bus and transport in London has always been a big part of my life.
"The cost of a fare in London has risen for eight years in a row and now that I'm mayor I am determined to prevent the cost of travel from becoming a barrier to work.
"The Hopper fare will make life cheaper and easier for millions of Londoners, and will help ensure that everyone will be able to afford to travel around the city.
"It is just the start of my plan to ensure that travelling around London is affordable for everyone, a commitment that includes a freeze on TfL fares for four years - benefiting millions of people."
London's transport commissioner, Mike Brown, said: "This new option will benefit a huge number of our passengers. For many people catching more than one bus is the only way they can get from A to B."