The news comes second hand from NME via Mustard magazine, which interviewed Moore about his new magazine Dodgem Logic. (Read the first four pages of the interview on Mustard's Website.) Moore seems affable in the text, though he gives characteristically long answers. And he promises that Gorillaz will appear in a forthcoming issue of Dodgem.
As for the opera, Hewlett and Albarn both have referred to it as a Gorillaz/not-Gorillaz project, possibly titled Carousel. [Not to be confused with the 1945 Broadway hit by Rodgers & Hammerstein. -- ed.]
You may commence making Gorillaz/Watchmen/V for Vendetta jokes now.