A "stop smoking" game for smartphones has been developed that incorporates elements of cognitive behavioural therapy (CBT).
The app, designed by a group of medical students, is the first to deliver personalised behavioural support to those wanting to quit tobacco.
It is based around concepts of CBT, the popular "talking treatment" that helps people change the way they think and behave.
To motivate users, the app has game-like features for reaching personal targets and tracking progress, with videos delivered by an animated personal doctor.
Currently, the NHS only provides behavioural support to around 9% of UK smokers who want to quit.
Yusuf Sherwani, a medical student at Imperial College London - who led development of the app, said: "As medical students, almost every day we see patients who are suffering from the consequences of smoking cigarettes; many of whom want to quit but lack the necessary support.
"We really hope this app takes off and transforms the support available to them. We believe it could be a game-changer."
Details of the project were presented at the British Thoracic Society Winter Meeting in London.
Dr Sanjay Agrawal, consultant lung specialist and chair of the British Thoracic Society's Tobacco Special Advisory Group, said: "This is a really interesting prototype and we look forward to seeing further developments of the game and research about its effectiveness.
"I like the idea of combining cognitive behavioural theory with the power of fun in a stop smoking game. Its other potential benefits are its cost effectiveness and sheer reach by using smartphone technology. We'll await further results with interest."
More information on the app, Quit Genius, can be found at www.quitgenius.com.