Robbie Williams? (from US, best friend used to have "Millennium" on repeat for a spell) I honestly thought at first that this was a Jonas brother or maybe post-reconstructive surgery Zac Ephron, but that didn't make sense with the UK part of the question.

Edit: I see I'm correct. But I honestly only dug into that part of my mind because I recalled both the aforementioned single and the general thing, stemming back to those days, that he was like huge in the UK but practically nowhere else. In other words, the question itself served as a clue to who he was (meaning he is apophatic--I only recognize him because I am aware of his absence)