But not too unorthodox, obviously. Bruno Mars didn't become the whoppingly successful songwriter and producer he is by veering too far off the pop/R&B/hip-hop course, so his second album is the same conventional mish-mash as his 6m-selling debut. There's no doubt, though, that he can write a pleasant tune, and sing it with sweet sincerity. Genre-hopping pop albums are a bit of a thing at the moment – witness similar releases by JLS and Kimbra – but Mars is an exceptionally nimble hopper. Lovelorn 1970s pop (Young Girls), Police-inspired reggae (Locked Out of Heaven), sprightly disco thumpers (Treasure): they're all in a day's work for him, and each is as unshakably catchy as the next. But Unorthodox Jukebox offers a bit more than clinically perfect songcraft – it also reveals Mars's bleak view of the women in his life. In Natalie, he even contemplates killing his beloved ("I'd spend a lifetime in jail, I'll be smiling in my cell"), revealing an unpleasantness you'd rather he had kept to himself.