The boy bands that spring to mind are the Backstreet Boys and Brother Beyond. Depending on the definition of boy band you could include Bellamy Brothers or Blues Brothers or Beach Boys.
I can't immediately think of a song though in the form 11CT
Thanks - I was on the wrong track looking for a song title- although I did consider 11 Chart Toppers by the Backstreet Boys but I think they had oly one (and none in US)
I'm not doubting it's Backsteet Boys (and the 11 concert tours looks good if that's what they've done). The clue here didn't mention anything about other letters