The French manufacturer will supply its TopSeries system to the flag-carrier's expanded fleet. Terms of the agreement have not been disclosed.
Thales says the British Airways installation will include 15.4in, 12.1in, 10.6in and 8.9in screens in the airline's first-class, business-class, premium-economy and economy cabins respectively.
The system's library will give passengers access to over 100 films, 300 programmes and 400 CDs as well as radio entertainment and podcasts.
Each seat throughout the cabin will have jack ports for personal electronic device connection and charging, and power sockets for laptop computers.
"It is an 'everything on demand' system that lets passengers do what they want, when they want," says BA general manager for product management Jamie Cassidy.
BA is acquiring 12 A380s and 24 787s, as well as six interim 777-300ERs for long-haul fleet modernisation.