Boeing included a very effective white noise generator as standard in the 777 series aircraft. It also has a secondary function as a ventilation system.

So you won't hear much of anything else: neither galley prep, nor other passengers. nor your travel companion, nor the IFE through BA's headphones, nor anything else.

Don your earplugs or good noise cancelling headphones according to preference and enjoy your flight; plugged into the IFE, such headphones will allow you to hear the soundtrack.