If one, two, three is a hit song, where is the cryptic aspect?
It's more likely to be something like Right Order if there is such a group. Also the clue states pop stars and groups, not song titles.
Good thinking topspin - I'll have to give it more consideration. I've already trawled through my Top Singles book. However, Eden Kane fits the clue very well and the clue is one of his/their hits. Totally confused now.