Northern Ireland is part of the United Kingdom but is not part of Great Britain. Neither are the Isle of Man, Anglesey or The Isle of Wight.
Great Britain is the island that includes most of England, Wales and Scotland.
It's a confusing one. N ireland is not, of course, part of Great Britain, which is a separate island. But is British. And "Britain" is another word for United Kingdom.
So really the celebrity is incorrect.
yeah sozza boys - great britain ( as opposed to little britain or brittany - the same word in most european languages 0 is the island of england and scotland.
actually the subject of legislation - James in 1603 wondered what to call himself - titular act 1 Jas VI &1 1603
Whilst Dec was of course right, to be fair to all those that called Ant & Dec thick/stupid, it doesn't help that the UK olympic team (which includes NI) calls itself team GB