Wasn’t there a commercial aired in the US, I believe it was for beer, perhaps even Guinness, that used the term “Brilliant!” for its bearded character?
As with most things in the Twitter age, many people in UK now use the term ‘brill’ when they mean ‘Brilliant’ ( excellent, very good, etc etc ), but don’t shorten the word when they mean that someone is extremely clever or skilful. Its also used sarcastically when something goes wrong “Oh Brilliant !”
notoneoffbritishisms.com 
Well lit ?
Wasn’t there a commercial aired in the US, I believe it was for beer, perhaps even Guinness, that used the term “Brilliant!” for its bearded character?
As with most things in the Twitter age, many people in UK now use the term ‘brill’ when they mean ‘Brilliant’ ( excellent, very good, etc etc ), but don’t shorten the word when they mean that someone is extremely clever or skilful. Its also used sarcastically when something goes wrong “Oh Brilliant !”
Aye, Mike S is correct, Brilliant gets shortened to Brill a lot of the time, especially by younger people from the south-east of england.