Jack Neo, the director of I NOT STUPID, is listed in the opening credits of THE MIRROR as an actor (though I can't load up stills yet) and does indeed appear in the film.

[url]hkmdb.com/db/movies/view.mhtml?id=8441[/url]

The DB cast list includes a Leung Chi-keung which seems to coincide with his Mandarin alias at IMDB:

http://www.imdb.com/name/nm0626090

Can an alias be added?

done.