Sean Gilman’s review published on Letterboxd :
Takeshi Kaneshiro goes to China to make a movie for Jackie Cheung. It's a musical and co-stars Zhou Xun, the story of the film being that she and Kaneshiro had been in love, but she has amnesia and has forgotten him, in love now with a circus master (to be played by Cheung). But ten years earlier, before they were movie stars, Kaneshiro and Zhou had been in love, and now she's pretending she doesn't know him, having apparently forgot their time together. She's been with Cheung for some time both professionally and romantically. There's lots of singing, lots of crying, lots of digitally hypercolored Beijing and snowy streets and movie sets.
Director Peter Chan cuts freely between the three levels of the narrative (the present reality, the movie within the movie, and ten years ago), with the musical's songs peppered throughout (the songs are strictly confined to the movie within the movie, but since that movie is essential about the events occurring in the present reality, the musical effect of expressing emotion through song is achieved without compromising the reality of the "real"). The songs are split in style between pop ballads for Kaneshiro, big Broadway-esque group numbers for the movie's chorus (a little bit Bob Fosse, a little bit Andrew Lloyd Webber), and dramatic song monologues for Cheung in the Les Miserables-style. The actors all do their own singing and are terrific, Cheung in particular was impressive, I bet he would have been fantastic in the Russell Crowe part in that Tom Hooper abomination.